diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/HOWTO | 20 | ||||
| -rw-r--r-- | Documentation/MSI-HOWTO.txt | 63 | ||||
| -rw-r--r-- | Documentation/feature-removal-schedule.txt | 2 | ||||
| -rw-r--r-- | Documentation/kernel-parameters.txt | 5 | ||||
| -rw-r--r-- | Documentation/s390/CommonIO | 2 | ||||
| -rw-r--r-- | Documentation/s390/cds.txt | 52 | ||||
| -rw-r--r-- | Documentation/s390/driver-model.txt | 3 |
7 files changed, 116 insertions, 31 deletions
diff --git a/Documentation/HOWTO b/Documentation/HOWTO index d6f3dd1..8d51c14 100644 --- a/Documentation/HOWTO +++ b/Documentation/HOWTO @@ -395,6 +395,26 @@ bugme-janitor mailing list (every change in the bugzilla is mailed here) +Managing bug reports +-------------------- + +One of the best ways to put into practice your hacking skills is by fixing +bugs reported by other people. Not only you will help to make the kernel +more stable, you'll learn to fix real world problems and you will improve +your skills, and other developers will be aware of your presence. Fixing +bugs is one of the best ways to get merits among other developers, because +not many people like wasting time fixing other people's bugs. + +To work in the already reported bug reports, go to http://bugzilla.kernel.org. +If you want to be advised of the future bug reports, you can subscribe to the +bugme-new mailing list (only new bug reports are mailed here) or to the +bugme-janitor mailing list (every change in the bugzilla is mailed here) + + http://lists.osdl.org/mailman/listinfo/bugme-new + http://lists.osdl.org/mailman/listinfo/bugme-janitors + + + Mailing lists ------------- diff --git a/Documentation/MSI-HOWTO.txt b/Documentation/MSI-HOWTO.txt index c70306a..5c34910 100644 --- a/Documentation/MSI-HOWTO.txt +++ b/Documentation/MSI-HOWTO.txt @@ -470,7 +470,68 @@ LOC: 324553 325068 ERR: 0 MIS: 0 -6. FAQ +6. MSI quirks + +Several PCI chipsets or devices are known to not support MSI. +The PCI stack provides 3 possible levels of MSI disabling: +* on a single device +* on all devices behind a specific bridge +* globally + +6.1. Disabling MSI on a single device + +Under some circumstances, it might be required to disable MSI on a +single device, It may be achived by either not calling pci_enable_msi() +or all, or setting the pci_dev->no_msi flag before (most of the time +in a quirk). + +6.2. Disabling MSI below a bridge + +The vast majority of MSI quirks are required by PCI bridges not +being able to route MSI between busses. In this case, MSI have to be +disabled on all devices behind this bridge. It is achieves by setting +the PCI_BUS_FLAGS_NO_MSI flag in the pci_bus->bus_flags of the bridge +subordinate bus. There is no need to set the same flag on bridges that +are below the broken brigde. When pci_enable_msi() is called to enable +MSI on a device, pci_msi_supported() takes care of checking the NO_MSI +flag in all parent busses of the device. + +Some bridges actually support dynamic MSI support enabling/disabling +by changing some bits in their PCI configuration space (especially +the Hypertransport chipsets such as the nVidia nForce and Serverworks +HT2000). It may then be required to update the NO_MSI flag on the +corresponding devices in the sysfs hierarchy. To enable MSI support +on device "0000:00:0e", do: + + echo 1 > /sys/bus/pci/devices/0000:00:0e/msi_bus + +To disable MSI support, echo 0 instead of 1. Note that it should be +used with caution since changing this value might break interrupts. + +6.3. Disabling MSI globally + +Some extreme cases may require to disable MSI globally on the system. +For now, the only known case is a Serverworks PCI-X chipsets (MSI are +not supported on several busses that are not all connected to the +chipset in the Linux PCI hierarchy). In the vast majority of other +cases, disabling only behind a specific bridge is enough. + +For debugging purpose, the user may also pass pci=nomsi on the kernel +command-line to explicitly disable MSI globally. But, once the appro- +priate quirks are added to the kernel, this option should not be +required anymore. + +6.4. Finding why MSI cannot be enabled on a device + +Assuming that MSI are not enabled on a device, you should look at +dmesg to find messages that quirks may output when disabling MSI +on some devices, some bridges or even globally. +Then, lspci -t gives the list of bridges above a device. Reading +/sys/bus/pci/devices/0000:00:0e/msi_bus will tell you whether MSI +are enabled (1) or disabled (0). In 0 is found in a single bridge +msi_bus file above the device, MSI cannot be enabled. + +7. FAQ Q1. Are there any limitations on using the MSI? diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 24f3c63..1ac3c74 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -255,7 +255,7 @@ Who: Stephen Hemminger <shemminger@osdl.org> What: PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment -When: Oktober 2008 +When: October 2008 Why: The stacking of class devices makes these values misleading and inconsistent. Class devices should not carry any of these properties, and bus diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index ff571f9..dd00fd5 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1231,6 +1231,11 @@ and is between 256 and 4096 characters. It is defined in the file machine check when some devices' config space is read. But various workarounds are disabled and some IOMMU drivers will not work. + bfsort Sort PCI devices into breadth-first order. + This sorting is done to get a device + order compatible with older (<= 2.4) kernels. + nobfsort Don't sort PCI devices into breadth-first order. + pcmv= [HW,PCMCIA] BadgePAD 4 pd. [PARIDE] diff --git a/Documentation/s390/CommonIO b/Documentation/s390/CommonIO index 59d1166..d684a6a 100644 --- a/Documentation/s390/CommonIO +++ b/Documentation/s390/CommonIO @@ -66,7 +66,7 @@ Command line parameters When a device is un-ignored, device recognition and sensing is performed and the device driver will be notified if possible, so the device will become - available to the system. + available to the system. Note that un-ignoring is performed asynchronously. You can also add ranges of devices to be ignored by piping to /proc/cio_ignore; "add <device range>, <device range>, ..." will ignore the diff --git a/Documentation/s390/cds.txt b/Documentation/s390/cds.txt index d80e573..32a96cc 100644 --- a/Documentation/s390/cds.txt +++ b/Documentation/s390/cds.txt @@ -174,14 +174,10 @@ read_dev_chars() - Read Device Characteristics This routine returns the characteristics for the device specified. -The function is meant to be called with an irq handler in place; that is, +The function is meant to be called with the device already enabled; that is, at earliest during set_online() processing. -While the request is processed synchronously, the device interrupt -handler is called for final ending status. In case of error situations the -interrupt handler may recover appropriately. The device irq handler can -recognize the corresponding interrupts by the interruption parameter be -0x00524443. The ccw_device must not be locked prior to calling read_dev_chars(). +The ccw_device must not be locked prior to calling read_dev_chars(). The function may be called enabled or disabled. @@ -410,26 +406,7 @@ individual flag meanings. Usage Notes : -Prior to call ccw_device_start() the device driver must assure disabled state, -i.e. the I/O mask value in the PSW must be disabled. This can be accomplished -by calling local_save_flags( flags). The current PSW flags are preserved and -can be restored by local_irq_restore( flags) at a later time. - -If the device driver violates this rule while running in a uni-processor -environment an interrupt might be presented prior to the ccw_device_start() -routine returning to the device driver main path. In this case we will end in a -deadlock situation as the interrupt handler will try to obtain the irq -lock the device driver still owns (see below) ! - -The driver must assure to hold the device specific lock. This can be -accomplished by - -(i) spin_lock(get_ccwdev_lock(cdev)), or -(ii) spin_lock_irqsave(get_ccwdev_lock(cdev), flags) - -Option (i) should be used if the calling routine is running disabled for -I/O interrupts (see above) already. Option (ii) obtains the device gate und -puts the CPU into I/O disabled state by preserving the current PSW flags. +ccw_device_start() must be called disabled and with the ccw device lock held. The device driver is allowed to issue the next ccw_device_start() call from within its interrupt handler already. It is not required to schedule a @@ -488,7 +465,7 @@ int ccw_device_resume(struct ccw_device *cdev); cdev - ccw_device the resume operation is requested for -The resume_IO() function returns: +The ccw_device_resume() function returns: 0 - suspended channel program is resumed -EBUSY - status pending @@ -507,6 +484,8 @@ a long-running channel program or the device might require to initially issue a halt subchannel (HSCH) I/O command. For those purposes the ccw_device_halt() command is provided. +ccw_device_halt() must be called disabled and with the ccw device lock held. + int ccw_device_halt(struct ccw_device *cdev, unsigned long intparm); @@ -517,7 +496,7 @@ intparm : interruption parameter; value is only used if no I/O The ccw_device_halt() function returns : - 0 - successful completion or request successfully initiated + 0 - request successfully initiated -EBUSY - the device is currently busy, or status pending. -ENODEV - cdev invalid. -EINVAL - The device is not operational or the ccw device is not online. @@ -533,6 +512,23 @@ can then perform an appropriate action. Prior to interrupt of an outstanding read to a network device (with or without PCI flag) a ccw_device_halt() is required to end the pending operation. +ccw_device_clear() - Terminage I/O Request Processing + +In order to terminate all I/O processing at the subchannel, the clear subchannel +(CSCH) command is used. It can be issued via ccw_device_clear(). + +ccw_device_clear() must be called disabled and with the ccw device lock held. + +int ccw_device_clear(struct ccw_device *cdev, unsigned long intparm); + +cdev: ccw_device the clear operation is requested for +intparm: interruption parameter (see ccw_device_halt()) + +The ccw_device_clear() function returns: + + 0 - request successfully initiated +-ENODEV - cdev invalid +-EINVAL - The device is not operational or the ccw device is not online. Miscellaneous Support Routines diff --git a/Documentation/s390/driver-model.txt b/Documentation/s390/driver-model.txt index 62c0823..77bf450 100644 --- a/Documentation/s390/driver-model.txt +++ b/Documentation/s390/driver-model.txt @@ -239,6 +239,9 @@ status - Can be 'online' or 'offline'. type - The physical type of the channel path. +shared - Whether the channel path is shared. + +cmg - The channel measurement group. 3. System devices ----------------- |