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path: root/drivers/pci/hotplug/acpiphp_glue.c
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2013-11-14PCI: Fix whitespace, capitalization, and spelling errorsBjorn Helgaas
Fix whitespace, capitalization, and spelling errors. No functional change. I know "busses" is not an error, but "buses" was more common, so I used it consistently. Signed-off-by: Marta Rybczynska <rybczynska@gmail.com> (pci_reset_bridge_secondary_bus()) Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-11-14Merge tag 'pci-v3.13-changes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci Pull PCI changes from Bjorn Helgaas: "Resource management - Fix host bridge window coalescing (Alexey Neyman) - Pass type, width, and prefetchability for window alignment (Wei Yang) PCI device hotplug - Convert acpiphp, acpiphp_ibm to dynamic debug (Lan Tianyu) Power management - Remove pci_pm_complete() (Liu Chuansheng) MSI - Fail initialization if device is not in PCI_D0 (Yijing Wang) MPS (Max Payload Size) - Use pcie_get_mps() and pcie_set_mps() to simplify code (Yijing Wang) - Use pcie_set_readrq() to simplify code (Yijing Wang) - Use cached pci_dev->pcie_mpss to simplify code (Yijing Wang) SR-IOV - Enable upstream bridges even for VFs on virtual buses (Bjorn Helgaas) - Use pci_is_root_bus() to avoid catching virtual buses (Wei Yang) Virtualization - Add x86 MSI masking ops (Konrad Rzeszutek Wilk) Freescale i.MX6 - Support i.MX6 PCIe controller (Sean Cross) - Increase link startup timeout (Marek Vasut) - Probe PCIe in fs_initcall() (Marek Vasut) - Fix imprecise abort handler (Tim Harvey) - Remove redundant of_match_ptr (Sachin Kamat) Renesas R-Car - Support Gen2 internal PCIe controller (Valentine Barshak) Samsung Exynos - Add MSI support (Jingoo Han) - Turn off power when link fails (Jingoo Han) - Add Jingoo Han as maintainer (Jingoo Han) - Add clk_disable_unprepare() on error path (Wei Yongjun) - Remove redundant of_match_ptr (Sachin Kamat) Synopsys DesignWare - Add irq_create_mapping() (Pratyush Anand) - Add header guards (Seungwon Jeon) Miscellaneous - Enable native PCIe services by default on non-ACPI (Andrew Murray) - Cleanup _OSC usage and messages (Bjorn Helgaas) - Remove pcibios_last_bus boot option on non-x86 (Bjorn Helgaas) - Convert bus code to use bus_, drv_, and dev_groups (Greg Kroah-Hartman) - Remove unused pci_mem_start (Myron Stowe) - Make sysfs functions static (Sachin Kamat) - Warn on invalid return from driver probe (Stephen M. Cameron) - Remove Intel Haswell D3 delays (Todd E Brandt) - Call pci_set_master() in core if driver doesn't do it (Yinghai Lu) - Use pci_is_pcie() to simplify code (Yijing Wang) - Use PCIe capability accessors to simplify code (Yijing Wang) - Use cached pci_dev->pcie_cap to simplify code (Yijing Wang) - Removed unused "is_pcie" from struct pci_dev (Yijing Wang) - Simplify sysfs CPU affinity implementation (Yijing Wang)" * tag 'pci-v3.13-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (79 commits) PCI: Enable upstream bridges even for VFs on virtual buses PCI: Add pci_upstream_bridge() PCI: Add x86_msi.msi_mask_irq() and msix_mask_irq() PCI: Warn on driver probe return value greater than zero PCI: Drop warning about drivers that don't use pci_set_master() PCI: Workaround missing pci_set_master in pci drivers powerpc/pci: Use pci_is_pcie() to simplify code [fix] PCI: Update pcie_ports 'auto' behavior for non-ACPI platforms PCI: imx6: Probe the PCIe in fs_initcall() PCI: Add R-Car Gen2 internal PCI support PCI: imx6: Remove redundant of_match_ptr PCI: Report pci_pme_active() kmalloc failure mn10300/PCI: Remove useless pcibios_last_bus frv/PCI: Remove pcibios_last_bus PCI: imx6: Increase link startup timeout PCI: exynos: Remove redundant of_match_ptr PCI: imx6: Fix imprecise abort handler PCI: Fail MSI/MSI-X initialization if device is not in PCI_D0 PCI: imx6: Remove redundant dev_err() in imx6_pcie_probe() x86/PCI: Coalesce multiple overlapping host bridge windows ...
2013-11-14Merge tag 'pm+acpi-3.13-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull ACPI and power management updates from Rafael J Wysocki: - New power capping framework and the the Intel Running Average Power Limit (RAPL) driver using it from Srinivas Pandruvada and Jacob Pan. - Addition of the in-kernel switching feature to the arm_big_little cpufreq driver from Viresh Kumar and Nicolas Pitre. - cpufreq support for iMac G5 from Aaro Koskinen. - Baytrail processors support for intel_pstate from Dirk Brandewie. - cpufreq support for Midway/ECX-2000 from Mark Langsdorf. - ARM vexpress/TC2 cpufreq support from Sudeep KarkadaNagesha. - ACPI power management support for the I2C and SPI bus types from Mika Westerberg and Lv Zheng. - cpufreq core fixes and cleanups from Viresh Kumar, Srivatsa S Bhat, Stratos Karafotis, Xiaoguang Chen, Lan Tianyu. - cpufreq drivers updates (mostly fixes and cleanups) from Viresh Kumar, Aaro Koskinen, Jungseok Lee, Sudeep KarkadaNagesha, Lukasz Majewski, Manish Badarkhe, Hans-Christian Egtvedt, Evgeny Kapaev. - intel_pstate updates from Dirk Brandewie and Adrian Huang. - ACPICA update to version 20130927 includig fixes and cleanups and some reduction of divergences between the ACPICA code in the kernel and ACPICA upstream in order to improve the automatic ACPICA patch generation process. From Bob Moore, Lv Zheng, Tomasz Nowicki, Naresh Bhat, Bjorn Helgaas, David E Box. - ACPI IPMI driver fixes and cleanups from Lv Zheng. - ACPI hotplug fixes and cleanups from Bjorn Helgaas, Toshi Kani, Zhang Yanfei, Rafael J Wysocki. - Conversion of the ACPI AC driver to the platform bus type and multiple driver fixes and cleanups related to ACPI from Zhang Rui. - ACPI processor driver fixes and cleanups from Hanjun Guo, Jiang Liu, Bartlomiej Zolnierkiewicz, Mathieu Rhéaume, Rafael J Wysocki. - Fixes and cleanups and new blacklist entries related to the ACPI video support from Aaron Lu, Felipe Contreras, Lennart Poettering, Kirill Tkhai. - cpuidle core cleanups from Viresh Kumar and Lorenzo Pieralisi. - cpuidle drivers fixes and cleanups from Daniel Lezcano, Jingoo Han, Bartlomiej Zolnierkiewicz, Prarit Bhargava. - devfreq updates from Sachin Kamat, Dan Carpenter, Manish Badarkhe. - Operation Performance Points (OPP) core updates from Nishanth Menon. - Runtime power management core fix from Rafael J Wysocki and update from Ulf Hansson. - Hibernation fixes from Aaron Lu and Rafael J Wysocki. - Device suspend/resume lockup detection mechanism from Benoit Goby. - Removal of unused proc directories created for various ACPI drivers from Lan Tianyu. - ACPI LPSS driver fix and new device IDs for the ACPI platform scan handler from Heikki Krogerus and Jarkko Nikula. - New ACPI _OSI blacklist entry for Toshiba NB100 from Levente Kurusa. - Assorted fixes and cleanups related to ACPI from Andy Shevchenko, Al Stone, Bartlomiej Zolnierkiewicz, Colin Ian King, Dan Carpenter, Felipe Contreras, Jianguo Wu, Lan Tianyu, Yinghai Lu, Mathias Krause, Liu Chuansheng. - Assorted PM fixes and cleanups from Andy Shevchenko, Thierry Reding, Jean-Christophe Plagniol-Villard. * tag 'pm+acpi-3.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (386 commits) cpufreq: conservative: fix requested_freq reduction issue ACPI / hotplug: Consolidate deferred execution of ACPI hotplug routines PM / runtime: Use pm_runtime_put_sync() in __device_release_driver() ACPI / event: remove unneeded NULL pointer check Revert "ACPI / video: Ignore BIOS initial backlight value for HP 250 G1" ACPI / video: Quirk initial backlight level 0 ACPI / video: Fix initial level validity test intel_pstate: skip the driver if ACPI has power mgmt option PM / hibernate: Avoid overflow in hibernate_preallocate_memory() ACPI / hotplug: Do not execute "insert in progress" _OST ACPI / hotplug: Carry out PCI root eject directly ACPI / hotplug: Merge device hot-removal routines ACPI / hotplug: Make acpi_bus_hot_remove_device() internal ACPI / hotplug: Simplify device ejection routines ACPI / hotplug: Fix handle_root_bridge_removal() ACPI / hotplug: Refuse to hot-remove all objects with disabled hotplug ACPI / scan: Start matching drivers after trying scan handlers ACPI: Remove acpi_pci_slot_init() headers from internal.h ACPI / blacklist: fix name of ThinkPad Edge E530 PowerCap: Fix build error with option -Werror=format-security ... Conflicts: arch/arm/mach-omap2/opp.c drivers/Kconfig drivers/spi/spi.c
2013-11-07Merge branch 'acpi-hotplug'Rafael J. Wysocki
* acpi-hotplug: ACPI / hotplug: Consolidate deferred execution of ACPI hotplug routines ACPI / hotplug: Do not execute "insert in progress" _OST ACPI / hotplug: Carry out PCI root eject directly ACPI / hotplug: Merge device hot-removal routines ACPI / hotplug: Make acpi_bus_hot_remove_device() internal ACPI / hotplug: Simplify device ejection routines ACPI / hotplug: Fix handle_root_bridge_removal() ACPI / hotplug: Refuse to hot-remove all objects with disabled hotplug ACPI / scan: Start matching drivers after trying scan handlers ACPI: Remove acpi_pci_slot_init() headers from internal.h Conflicts: include/acpi/acpiosxf.h (with the 'acpica' branch)
2013-11-07ACPI / hotplug: Consolidate deferred execution of ACPI hotplug routinesRafael J. Wysocki
There are two different interfaces for queuing up work items on the ACPI hotplug workqueue, alloc_acpi_hp_work() used by PCI and PCI host bridge hotplug code and acpi_os_hotplug_execute() used by the common ACPI hotplug code and docking stations. They both are somewhat cumbersome to use and work slightly differently. The users of alloc_acpi_hp_work() have to submit a work function that will extract the necessary data items from a struct acpi_hp_work object allocated by alloc_acpi_hp_work() and then will free that object, while it would be more straightforward to simply use a work function with one more argument and let the interface take care of the execution details. The users of acpi_os_hotplug_execute() also have to deal with the fact that it takes only one argument in addition to the work function pointer, although acpi_os_execute_deferred() actually takes care of the allocation and freeing of memory, so it would have been able to pass more arguments to the work function if it hadn't been constrained by the connection with acpi_os_execute(). Moreover, while alloc_acpi_hp_work() makes GFP_KERNEL memory allocations, which is correct, because hotplug work items are always queued up from process context, acpi_os_hotplug_execute() uses GFP_ATOMIC, as that is needed by acpi_os_execute(). Also, acpi_os_execute_deferred() queued up by it waits for the ACPI event workqueues to flush before executing the work function, whereas alloc_acpi_hp_work() can't do anything similar. That leads to somewhat arbitrary differences in behavior between various ACPI hotplug code paths and has to be straightened up. For this reason, replace both alloc_acpi_hp_work() and acpi_os_hotplug_execute() with a single interface, acpi_hotplug_execute(), combining their behavior and being more friendly to its users than any of the two. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-10-30Revert "ACPI / hotplug / PCI: Avoid doing too much for spurious notifies"Mika Westerberg
Commit 2dc4128 (ACPI / hotplug / PCI: Avoid doing too much for spurious notifies) changed the enable_slot() to check return value of pci_scan_slot() and if it is zero return early from the function. It means that there were no new devices in this particular slot. However, if a device appeared deeper in the hierarchy the code now ignores it causing things like Thunderbolt chaining fail to recognize new devices. The problem with Alex Williamson's machine was solved with commit a47d8c8 (ACPI / hotplug / PCI: Avoid parent bus rescans on spurious device checks) and hence we should be able to restore the original functionality that we always rescan on bus check notification. On a device check notification we still check what acpiphp_rescan_slot() returns and on zero bail out early. Fixes: 2dc41281b1d1 (ACPI / hotplug / PCI: Avoid doing too much for spurious notifies) Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Tested-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-11ACPI / hotplug / PCI: Drop WARN_ON() from acpiphp_enumerate_slots()Rafael J. Wysocki
The WARN_ON() in acpiphp_enumerate_slots() triggers unnecessarily for devices whose bridges are going to be handled by native PCIe hotplug (pciehp) and the simplest way to prevent that from happening is to drop the WARN_ON(). References: https://bugzilla.kernel.org/show_bug.cgi?id=62831 Reported-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-11ACPI / hotplug / PCI: Fix error code path in acpiphp_enumerate_slots()Rafael J. Wysocki
One of the error code paths in acpiphp_enumerate_slots() is missing a pci_dev_put(bridge->pci_dev) call, so add it. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
2013-09-25PCI: acpiphp: Convert to dynamic debugLan Tianyu
This patch is to use pr_debug/info/warn/err to replace acpiphp debug functions and remove module's debug param. User interface change: before this patch, boot with the "acpiphp.debug" kernel parameter to turn on debug. After this patch, set CONFIG_DYNAMIC_DEBUG=y and boot with "acpiphp.dyndebug=+p" instead. See Documentation/dynamic-debug-howto.txt. [bhelgaas: changelog] Signed-off-by: Lan Tianyu <tianyu.lan@intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2013-09-10Merge branch 'acpi-pci-hotplug'Rafael J. Wysocki
* acpi-pci-hotplug: ACPI / hotplug / PCI: Avoid parent bus rescans on spurious device checks ACPI / hotplug / PCI: Use _OST to notify firmware about notify status ACPI / hotplug / PCI: Avoid doing too much for spurious notifies ACPI / hotplug / PCI: Don't trim devices before scanning the namespace
2013-09-09ACPI / hotplug / PCI: Avoid parent bus rescans on spurious device checksRafael J. Wysocki
In the current ACPIPHP notify handler we always go directly for a rescan of the parent bus if we get a device check notification for a device that is not a bridge. However, this obviously is overzealous if nothing really changes, because this way we may rescan the whole PCI hierarchy pretty much in vain. That happens on Alex Williamson's machine whose ACPI tables contain device objects that are supposed to coresspond to PCIe root ports, but those ports aren't physically present (or at least they aren't visible in the PCI config space to us). The BIOS generates multiple device check notifies for those objects during boot and for each of them we go straight for the parent bus rescan, but the parent bus is the root bus in this particular case. In consequence, we rescan the whole PCI bus from the top several times in a row, which is completely unnecessary, increases boot time by 50% (after previous fixes) and generates excess dmesg output from the PCI subsystem. Fix the problem by checking if we can find anything new in the slot corresponding to the device we've got a device check notify for and doing nothig if that's not the case. The spec (ACPI 5.0, Section 5.6.6) appears to mandate this behavior, as it says: Device Check. Used to notify OSPM that the device either appeared or disappeared. If the device has appeared, OSPM will re-enumerate from the parent. If the device has disappeared, OSPM will invalidate the state of the device. OSPM may optimize out re-enumeration. Therefore, according to the spec, we are free to do nothing if nothing changes. References: https://bugzilla.kernel.org/show_bug.cgi?id=60865 Reported-and-tested-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-09-07ACPI / hotplug / PCI: Use _OST to notify firmware about notify statusRafael J. Wysocki
The spec suggests that we should use _OST to notify the platform about the status of notifications it sends us, for example so that it doesn't repeate a notification that has been handled already. This turns out to help reduce the amount of diagnostic output from the ACPIPHP subsystem and speed up boot on at least one system that generates multiple device check notifies for PCIe devices on the root bus during boot. Reported-and-tested-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-09-07ACPI / hotplug / PCI: Avoid doing too much for spurious notifiesRafael J. Wysocki
Sometimes we may get a spurious device check or bus check notify for a hotplug device and in those cases we should avoid doing all of the configuration work needed when something actually changes. To that end, check the return value of pci_scan_slot() in enable_slot() and bail out early if it is 0. This turns out to help reduce the amount of diagnostic output from the ACPIPHP subsystem and speed up boot on at least one system that generates multiple device check notifies for PCIe devices on the root bus during boot. Reported-and-tested-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-09-05ACPI / hotplug / PCI: Don't trim devices before scanning the namespaceRafael J. Wysocki
In acpiphp_bus_add() we first remove device objects corresponding to the given handle and the ACPI namespace branch below it, which are then re-created by acpi_bus_scan(). This used to be done to clean up after surprise removals, but now we do the cleanup through trim_stale_devices() which checks if the devices in question are actually gone before removing them, so the device hierarchy trimming in acpiphp_bus_add() is not necessary any more and, moreover, it may lead to problems if it removes device objects corresponding to devices that are actually present. For this reason, remove the leftover acpiphp_bus_trim() from acpiphp_bus_add(). Reported-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-09-03Merge tag 'pci-v3.12-changes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci Pull PCI changes from Bjorn Helgaas: PCI device hotplug: - Use PCIe native hotplug, not ACPI hotplug, when possible (Neil Horman) - Assign resources on per-host bridge basis (Yinghai Lu) MPS (Max Payload Size): - Allow larger MPS settings below hotplug-capable Root Port (Yijing Wang) - Add warnings about unsafe MPS settings (Yijing Wang) - Simplify interface and messages (Bjorn Helgaas) SR-IOV: - Return -ENOSYS on non-SR-IOV devices (Stefan Assmann) - Update NumVFs register when disabling SR-IOV (Yijing Wang) Virtualization: - Add bus and slot reset support (Alex Williamson) - Fix ACS (Access Control Services) issues (Alex Williamson) Miscellaneous: - Simplify PCIe Capability accessors (Bjorn Helgaas) - Add pcibios_pm_ops for arch-specific hibernate stuff (Sebastian Ott) - Disable decoding during BAR sizing only when necessary (Zoltan Kiss) - Delay enabling bridges until they're needed (Yinghai Lu) - Split Designware support into Synopsys and Exynos parts (Jingoo Han) - Convert class code to use dev_groups (Greg Kroah-Hartman) - Cleanup Designware and Exynos I/O access wrappers (Seungwon Jeon) - Fix bridge I/O window alignment (Bjorn Helgaas) - Add pci_wait_for_pending_transaction() (Casey Leedom) - Use devm_ioremap_resource() in Marvell driver (Tushar Behera) * tag 'pci-v3.12-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (63 commits) PCI/ACPI: Fix _OSC ordering to allow PCIe hotplug use when available PCI: exynos: Add I/O access wrappers PCI: designware: Drop "addr" arg from dw_pcie_readl_rc()/dw_pcie_writel_rc() PCI: Remove pcie_cap_has_devctl() PCI: Support PCIe Capability Slot registers only for ports with slots PCI: Remove PCIe Capability version checks PCI: Allow PCIe Capability link-related register access for switches PCI: Add offsets of PCIe capability registers PCI: Tidy bitmasks and spacing of PCIe capability definitions PCI: Remove obsolete comment reference to pci_pcie_cap2() PCI: Clarify PCI_EXP_TYPE_PCI_BRIDGE comment PCI: Rename PCIe capability definitions to follow convention PCI: Warn if unsafe MPS settings detected PCI: Fix MPS peer-to-peer DMA comment syntax PCI: Disable decoding for BAR sizing only when it was actually enabled PCI: Add comment about needing pci_msi_off() even when CONFIG_PCI_MSI=n PCI: Add pcibios_pm_ops for optional arch-specific hibernate functionality PCI: Don't restrict MPS for slots below Root Ports PCI: Simplify MPS test for Downstream Port PCI: Remove unnecessary check for pcie_get_mps() failure ...
2013-08-17ACPI / hotplug / PCI: Fix NULL pointer dereference in cleanup_bridge()Rafael J. Wysocki
After commit bbd34fc (ACPI / hotplug / PCI: Register all devices under the given bridge) register_slot() is called for all PCI devices under a given bridge that have corresponding objects in the ACPI namespace, but it calls acpiphp_register_hotplug_slot() only for devices satisfying specific criteria. Still, cleanup_bridge() calls acpiphp_unregister_hotplug_slot() for all objects created by register_slot(), although it should only call it for the ones that acpiphp_register_hotplug_slot() has been called for (successfully). This causes a NULL pointer to be dereferenced by the acpiphp_unregister_hotplug_slot() executed by cleanup_bridge() if the object it is called for has not been passed to acpiphp_register_hotplug_slot(). To fix this problem, check if the 'slot' field of the object passed to acpiphp_unregister_hotplug_slot() in cleanup_bridge() is not NULL, which only is the case if acpiphp_register_hotplug_slot() has been executed for that object. In addition to that, make register_slot() reset the 'slot' field to NULL if acpiphp_register_hotplug_slot() has failed for the given object to prevent stale pointers from being used by acpiphp_unregister_hotplug_slot(). Reported-and-tested-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-25PCI: Delay enabling bridges until they're neededYinghai Lu
We currently enable PCI bridges after scanning a bus and assigning resources. This is often done in arch code. This patch changes this so we don't enable a bridge until necessary, i.e., until we enable a PCI device behind the bridge. We do this in the generic pci_enable_device() path, so this also removes the arch-specific code to enable bridges. [bhelgaas: changelog] Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2013-07-23ACPI / hotplug / PCI: Get rid of check_sub_bridges()Mika Westerberg
Now that acpiphp_check_bridge() always enumerates devices behind the bridge, there is no need to do that for each sub-bridge anymore like it is done in the current ACPI-based PCI hotplug (ACPIPHP) code. Given this we don't need check_sub_bridges() anymore, so drop that function completely. This also simplifies the ACPIPHP code a bit. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-23ACPI / hotplug / PCI: Clean up bridge_mutex usageRafael J. Wysocki
Do not acquire bridge_mutex around the addition of a slot to its bridge's list of slots and arount the addition of a function to its slot's list of functions, because that doesn't help anything right now (those lists are walked without any locking anyway). However, acquire bridge_mutex around the list walk in acpiphp_remove_slots() and use list_for_each_entry() there, because we terminate the walk as soon as we find the first matching entry. This prevents that list walk from colliding with bridge addition and removal. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Redefine enable_device() and disable_device()Rafael J. Wysocki
Notice that functions enable_device() and disable_device() cannot fail and their return values are ignored in the majority of places, so redefine them as void and use the opportunity to change their names to enable_slot() and disable_slot(), respectively, which much better reflects what they do. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Sanitize acpiphp_get_(latch)|(adapter)_status()Mika Westerberg
There is no need for a temporary variable and all the tricks with ternary operators in acpiphp_get_(latch)|(adapter)_status(). Change those functions to be a bit more straightforward. [rjw: Changelog] Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-23ACPI / hotplug / PCI: Check for new devices on enabled slotsRafael J. Wysocki
The current implementation of acpiphp_check_bridge() is pretty dumb: - It enables a slot if it's not enabled and the slot status is ACPI_STA_ALL. - It disables a slot if it's enabled and the slot status is not ACPI_STA_ALL. This behavior is not sufficient to handle the Thunderbolt daisy chaining case properly, however, because in that case the bus behind the already enabled slot needs to be rescanned for new devices. For this reason, modify acpiphp_check_bridge() so that slots are disabled and stopped if they are not in the ACPI_STA_ALL state. For slots in the ACPI_STA_ALL state, devices behind them that don't respond are trimmed using a new function, trim_stale_devices(), introduced specifically for this purpose. That function walks the given bus and checks each device on it. If the device doesn't respond, it is assumed to be gone and is removed. Once all of the stale devices directy behind the slot have been removed, acpiphp_check_bridge() will start looking for new devices that might have appeared on the given bus. It will do that even if the slot is already enabled (SLOT_ENABLED is set for it). In addition to that, make the bus check notification ignore SLOT_ENABLED and go for enable_device() directly if bridge is NULL, so that devices behind the slot are re-enumerated in that case too. This change is based on earlier patches from Kirill A Shutemov and Mika Westerberg. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Allow slots without new devices to be rescannedKirill A. Shutemov
Currently, enable_device() checks the return value of pci_scan_slot() and returns immediately if that's 0 (meaning that no new functions have been found in the slot). However, if one of the functions in the slot is a bridge, some new devices may appear below it even if the bridge itself is present continuously, so it generally is necessary to do the rescan anyway just in case. [In particular, that's necessary with the Thunderbolt daisy chaining in which case new devices may be connected to the existing ones down the chain.] The correctness of this change relies on the ability of pcibios_resource_survey_bus() to detect if it has already been called for the given bus and to skip it if so. Failure to do that will lead to resource allocation conflicts. [rjw: Changelog] Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-23ACPI / hotplug / PCI: Do not check SLOT_ENABLED in enable_device()Kirill A. Shutemov
With Thunderbolt you can daisy chain devices: connect new devices to an already plugged one. In that case the "hotplug slot" is already enabled, but we still want to look for new PCI devices behind it. Reuse enable_device() to scan for new PCI devices on enabled slots and push the SLOT_ENABLED check up into acpiphp_enable_slot(). [rjw: Rebased, modified the changelog] Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-23ACPI / hotplug / PCI: Do not exectute _PS0 and _PS3 directlyRafael J. Wysocki
The ACPI-based PCI hotplug (acpiphp) core code need not and really should not execute _PS0 and _PS3 directly for devices it handles. First of all, it is not necessary to put devices into D3 after acpi_bus_trim() has walked through them, because acpi_device_unregister() invoked by it puts each device into D3cold before returning. Thus after disable_device() the slot should be powered down already. Second, calling _PS0 directly on ACPI device objects may not be appropriate, because it may require power resources to be set up in a specific way in advance and that must be taken care of by the ACPI core. Thus modify acpiphp_bus_add() to power up the device using the appropriate interface after it has run acpi_bus_scan() on its handle. After that, the functions executing _PS0 and _PS3, power_on_slot() and power_off_slot(), are not necessary any more, so drop them and update the code calling them accordingly. Also drop the function flags related to device power states, since they aren't useful any more too. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Do not queue up event handling work items in vainRafael J. Wysocki
Modify handle_hotplug_event() to avoid queing up the execution of handle_hotplug_event_work_fn() as a work item on kacpi_hotplug_wq for non-hotplug events, such as ACPI_NOTIFY_DEVICE_WAKE. Move the code printing diagnostic messages for those events into handle_hotplug_event(). In addition to that, remove the bogus comment about how the core should distinguish between hotplug and non-hotplug events and queue them up on different workqueues. The core clearly cannot know in advance what events will be interesting to the given caller of acpi_install_notify_handler(). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Consolidate slot disabling and ejectingMika Westerberg
Both acpiphp_disable_slot() and acpiphp_eject_slot() are always called together so instead of calling each separately we can consolidate them into one function acpiphp_disable_and_eject_slot() that does both (but it will return success on _EJ0 failures that were ignored in the majority of call sites anyway). [rjw: Rebased plus minor tweaks] Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-23ACPI / hotplug / PCI: Drop redundant checks from check_hotplug_bridge()Rafael J. Wysocki
Two checks in check_hotplug_bridge() are redundant (they have been done by the caller already), so drop them. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Rework namespace scanning and trimming routinesRafael J. Wysocki
The acpiphp_bus_trim() and acpiphp_bus_add() functions need not return error codes that are never checked, so redefine them and simplify them a bit. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Store parent in functions and bus in slotsRafael J. Wysocki
To avoid chasing more pointers than necessary in some situations, move the bridge pointer from struct acpiphp_slot to struct acpiphp_func (and call it 'parent') and add a bus pointer to struct acpiphp_slot. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Drop handle field from struct acpiphp_bridgeRafael J. Wysocki
The handle field in struct acpiphp_bridge is only used by acpiphp_enumerate_slots(), but in that function the local handle variable can be used instead, so make that happen and drop handle from struct acpiphp_bridge. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Drop handle field from struct acpiphp_funcRafael J. Wysocki
The ACPI handle stored in struct acpiphp_func is also stored in the struct acpiphp_context object containing it and it is trivial to get from a struct acpiphp_func pointer to the handle field of the outer struct acpiphp_context. Hence, the handle field of struct acpiphp_func is redundant, so drop it and provide a helper function, func_to_handle(), allowing it users to get the ACPI handle for the given struct acpiphp_func pointer. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Embed function struct into struct acpiphp_contextRafael J. Wysocki
Since there has to be a struct acpiphp_func object for every struct acpiphp_context created by register_slot(), the struct acpiphp_func one can be embedded into the struct acpiphp_context one, which allows some code simplifications to be made. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Drop flags field from struct acpiphp_bridgeRafael J. Wysocki
The only bridge flag used by the ACPI-based PCI hotplug (ACPIPHP) code is BRIDGE_HAS_EJ0, but it is only used by the event handling function hotplug_event() and if that flag is set, the corresponding function flag FUNC_HAS_EJ0 is set as well, so that bridge flag is redundant. For this reason, drop BRIDGE_HAS_EJ0 and all code referring to it and since it is the only bridge flag defined, drop the flags field from struct acpiphp_bridge entirely. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Drop sun field from struct acpiphp_slotRafael J. Wysocki
If the slot unique number is passed as an additional argument to acpiphp_register_hotplug_slot(), the 'sun' field in struct acpiphp_slot is only used by ibm_[s|g]et_attention_status(), but then it's more efficient to store it in struct slot. Thus move the 'sun' field from struct acpiphp_slot to struct slot changing its data type to unsigned int in the process, and redefine acpiphp_register_hotplug_slot() to take the slot number as separate argument. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Register all devices under the given bridgeRafael J. Wysocki
Rework register_slot() to create a struct acpiphp_func object for every function it is called for and to create acpiphp slots for all of them. Although acpiphp_register_hotplug_slot() is only called for the slots whose functions are identified as "ejectable", so that user space can manipulate them, the ACPIPHP notify handler, handle_hotplug_event(), is now installed for all of the registered functions (that aren't dock stations) and hotplug events may be handled for all of them. As a result, essentially, all PCI bridges represented by objects in the ACPI namespace are now going to be "hotplug" bridges and that may affect resources allocation in general, although it shouldn't lead to problems. This allows the code to be simplified substantially and addresses the problem where bus check or device check notifications for some PCI bridges or devices are not handled, because those devices are not recognized as "ejectable" or there appear to be no "ejectable" devices under those bridges. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Refactor slot allocation code in register_slot()Rafael J. Wysocki
To make the code in register_slot() a bit easier to follow, change the way the slot allocation part is organized. Drop one local variable that's not used any more after that modification. This code change should not lead to any changes in behavior. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Drop func field from struct acpiphp_bridgeRafael J. Wysocki
Since the func pointer in struct acpiphp_context can always be used instead of the func pointer in struct acpiphp_bridge, drop the latter. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Merge hotplug event handling functionsRafael J. Wysocki
There are separate handling event functions for hotplug bridges and for hotplug functions, but they may be combined into one common hotplug event handling function which simplifies the code slightly. That also allows a theoretical bug to be dealt with which in principle may occur if a hotplug bridge is on a dock station, because in that case the bridge-specific notification should be used instead of the function-specific one, but the dock station always uses the latter. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Pass hotplug context objects to event handlersRafael J. Wysocki
Modify handle_hotplug_event() to pass the entire context object (instead of its fields individually) to work functions started by it. This change makes the subsequent consolidation of the event handling work functions a bit more straightforward. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Rework acpiphp_handle_to_bridge()Rafael J. Wysocki
Using the hotplug context objects introduced previously rework the ACPI-based PCI hotplug (ACPIPHP) core code to get to acpiphp_bridge objects associated with hotplug bridges from those context objects rather than from the global list of hotplug bridges. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Unified notify handler for hotplug eventsRafael J. Wysocki
Using the hotplug context objects introduced previously rework the ACPI-based PCI hotplug (ACPIPHP) core code so that all notifications for ACPI device objects corresponding to the hotplug PCI devices are handled by one function, handle_hotplug_event(), which recognizes whether it has to handle a bridge or a function. In addition to code size reduction it allows some ugly pieces of code where notify handlers have to be uninstalled and installed again to go away. Moreover, it fixes a theoretically possible race between handle_hotplug_event() and free_bridge() tearing down data structures for the same handle. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Hotplug context objects for bridges and functionsRafael J. Wysocki
When either a new hotplug bridge or a new hotplug function is added by the ACPI-based PCI hotplug (ACPIPHP) code, attach a context object to its ACPI handle to store hotplug-related information in it. To start with, put the handle's bridge and function pointers into that object. Count references to the context objects and drop them when they are not needed any more. First of all, this makes it possible to find out if the given bridge has been registered as a function already in a much more straightforward way and acpiphp_bridge_handle_to_function() can be dropped (Yay!). This also will allow some more simplifications to be made going forward. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Always return success after adding a functionRafael J. Wysocki
When a new ACPIPHP function is added by register_slot() and the notify handler cannot be installed for it, register_slot() returns an error status without cleaning up, which causes the entire namespace walk in acpiphp_enumerate_slots() to be aborted, although it still may be possible to successfully install the function notify handler for other device objects under the given brigde. To address this issue make register_slot() return success after a new function has been added, even if the addition of the notify handler for it has failed. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / hotplug / PCI: Consolidate acpiphp_enumerate_slots()Rafael J. Wysocki
The acpiphp_enumerate_slots() function is now split into two parts, acpiphp_enumerate_slots() proper and init_bridge_misc() which is only called by the former. If these functions are combined, it is possible to make the code easier to follow and to clean up the error handling (to prevent memory leaks on error from happening in particular), so do that. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-07-23ACPI / PCI: Make bus registration and unregistration symmetricRafael J. Wysocki
Since acpi_pci_slot_enumerate() and acpiphp_enumerate_slots() can get the ACPI device handle they need from bus->bridge, it is not necessary to pass that handle to them as an argument. Drop the second argument of acpi_pci_slot_enumerate() and acpiphp_enumerate_slots(), rework them to obtain the ACPI handle from bus->bridge and make acpi_pci_add_bus() and acpi_pci_remove_bus() entirely symmetrical. Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Yinghai Lu <yinghai@kernel.org>
2013-07-14ACPI / dock / PCI: Drop ACPI dock notifier chainRafael J. Wysocki
The only user of the ACPI dock notifier chain is the ACPI-based PCI hotplug (acpiphp) driver that uses it to carry out post-dock fixups needed by some systems with broken _DCK. However, it is not necessary to use a separate notifier chain for that, as it can be simply replaced with a new callback in struct acpi_dock_ops. For this reason, add a new .fixup() callback to struct acpi_dock_ops and make hotplug_dock_devices() execute it for all dock devices with hotplug operations registered. Accordingly, make acpiphp point that callback to the function carrying out the post-dock fixups and do not register a separate dock notifier for each device registering dock operations. Finally, drop the ACPI dock notifier chain that has no more users. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-14ACPI: simplify acpiphp driver with new helper functionsJiang Liu
Use the new helper functions introduced previously to simplify the ACPI-based PCI hotplug (acpiphp) driver. [rjw: Changelog] Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-06-24ACPI / dock / PCI: Synchronous handling of dock events for PCI devicesRafael J. Wysocki
The interactions between the ACPI dock driver and the ACPI-based PCI hotplug (acpiphp) are currently problematic because of ordering issues during hot-remove operations. First of all, the current ACPI glue code expects that physical devices will always be deleted before deleting the companion ACPI device objects. Otherwise, acpi_unbind_one() will fail with a warning message printed to the kernel log, for example: [ 185.026073] usb usb5: Oops, 'acpi_handle' corrupt [ 185.035150] pci 0000:1b:00.0: Oops, 'acpi_handle' corrupt [ 185.035515] pci 0000:18:02.0: Oops, 'acpi_handle' corrupt [ 180.013656] port1: Oops, 'acpi_handle' corrupt This means, in particular, that struct pci_dev objects have to be deleted before the struct acpi_device objects they are "glued" with. Now, the following happens the during the undocking of an ACPI-based dock station: 1) hotplug_dock_devices() invokes registered hotplug callbacks to destroy physical devices associated with the ACPI device objects depending on the dock station. It calls dd->ops->handler() for each of those device objects. 2) For PCI devices dd->ops->handler() points to handle_hotplug_event_func() that queues up a separate work item to execute _handle_hotplug_event_func() for the given device and returns immediately. That work item will be executed later. 3) hotplug_dock_devices() calls dock_remove_acpi_device() for each device depending on the dock station. This runs acpi_bus_trim() for each of them, which causes the underlying ACPI device object to be destroyed, but the work items queued up by handle_hotplug_event_func() haven't been started yet. 4) _handle_hotplug_event_func() queued up in step 2) are executed and cause the above failure to happen, because the PCI devices they handle do not have the companion ACPI device objects any more (those objects have been deleted in step 3). The possible breakage doesn't end here, though, because hotplug_dock_devices() may return before at least some of the _handle_hotplug_event_func() work items spawned by it have a chance to complete and then undock() will cause _DCK to be evaluated and that will cause the devices handled by the _handle_hotplug_event_func() to go away possibly while they are being accessed. This means that dd->ops->handler() for PCI devices should not point to handle_hotplug_event_func(). Instead, it should point to a function that will do the work of _handle_hotplug_event_func() synchronously. For this reason, introduce such a function, hotplug_event_func(), and modity acpiphp_dock_ops to point to it as the handler. Unfortunately, however, this is not sufficient, because if the dock code were not changed further, hotplug_event_func() would now deadlock with hotplug_dock_devices() that called it, since it would run unregister_hotplug_dock_device() which in turn would attempt to acquire the dock station's hp_lock mutex already acquired by hotplug_dock_devices(). To resolve that deadlock use the observation that unregister_hotplug_dock_device() won't need to acquire hp_lock if PCI bridges the devices on the dock station depend on are prevented from being removed prematurely while the first loop in hotplug_dock_devices() is in progress. To make that possible, introduce a mechanism by which the callers of register_hotplug_dock_device() can provide "init" and "release" routines that will be executed, respectively, during the addition and removal of the physical device object associated with the given ACPI device handle. Make acpiphp use two new functions, acpiphp_dock_init() and acpiphp_dock_release(), that call get_bridge() and put_bridge(), respectively, on the acpiphp bridge holding the given device, for this purpose. In addition to that, remove the dock station's list of "hotplug devices" and make the dock code always walk the whole list of "dependent devices" instead in such a way that the loops in hotplug_dock_devices() and dock_event() (replacing the loops over "hotplug devices") will take references to the list entries that register_hotplug_dock_device() has been called for. That prevents the "release" routines associated with those entries from being called while the given entry is being processed and for PCI devices this means that their bridges won't be removed (by a concurrent thread) while hotplug_event_func() handling them is being executed. This change is based on two earlier patches from Jiang Liu. References: https://bugzilla.kernel.org/show_bug.cgi?id=59501 Reported-and-tested-by: Alexander E. Patrakov <patrakov@gmail.com> Tracked-down-by: Jiang Liu <jiang.liu@huawei.com> Tested-by: Illya Klymov <xanf@xanf.me> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Yinghai Lu <yinghai@kernel.org> Cc: 3.9+ <stable@vger.kernel.org>
2013-06-22PCI / ACPI: Use boot-time resource allocation rules during hotplugJiang Liu
On x86 platforms, the kernel respects PCI resource assignments from the BIOS and only reassigns resources for unassigned BARs at boot time. However, with the ACPI-based hotplug (acpiphp), it ignores the BIOS' PCI resource assignments completely and reassigns all resources by itself. This causes differences in PCI resource allocation between boot time and runtime hotplug to occur, which is generally undesirable and sometimes actively breaks things. Namely, if there are enough resources, reassigning all PCI resources during runtime hotplug should work, but it may fail if the resources are constrained. This may happen, for instance, when some PCI devices with huge MMIO BARs are involved in the runtime hotplug operations, because the current PCI MMIO alignment algorithm may waste huge chunks of MMIO address space in those cases. On the Alexander's Sony VAIO VPCZ23A4R the BIOS allocates limited MMIO resources for the dock station which contains a device (graphics adapter) with a 256MB MMIO BAR. An attempt to reassign that during runtime hotplug causes the dock station MMIO window to be exhausted and acpiphp fails to allocate resources for the majority of devices on the dock station as a result. To prevent that from happening, modify acpiphp to follow the boot time resources allocation behavior so that the BIOS' resource assignments are respected during runtime hotplug too. [rjw: Changelog] References: https://bugzilla.kernel.org/show_bug.cgi?id=56531 Reported-and-tested-by: Alexander E. Patrakov <patrakov@gmail.com> Tested-by: Illya Klymov <xanf@xanf.me> Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Acked-by: Yinghai Lu <yinghai@kernel.org> Cc: 3.9+ <stable@vger.kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>