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path: root/drivers/gpu/drm/i915/intel_lrc.h
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2016-08-02drm/i915: Unify legacy/execlists submit_execbuf callbacksChris Wilson
Now that emitting requests is identical between legacy and execlists, we can use the same function to build up the ring for submitting to either engine. (With the exception of i915_switch_contexts(), but in time that will also be handled gracefully.) Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1469432687-22756-30-git-send-email-chris@chris-wilson.co.uk Link: http://patchwork.freedesktop.org/patch/msgid/1470174640-18242-21-git-send-email-chris@chris-wilson.co.uk
2016-08-02drm/i915: Unify request submissionChris Wilson
Move request submission from emit_request into its own common vfunc from i915_add_request(). v2: Convert I915_DISPATCH_flags to BIT(x) whilst passing v3: Rename a few functions to match. v4: Reenable execlists submission after disabling guc. v5: Be aware that everyone calls i915_guc_submission_disable()! Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Link: http://patchwork.freedesktop.org/patch/msgid/1469432687-22756-23-git-send-email-chris@chris-wilson.co.uk Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1470174640-18242-14-git-send-email-chris@chris-wilson.co.uk
2016-08-02drm/i915: Remove obsolete engine->gpu_caches_dirtyChris Wilson
Space for flushing the GPU cache prior to completing the request is preallocated and so cannot fail - the GPU caches will always be flushed along with the completed request. This means we no longer have to track whether the GPU cache is dirty between batches like we had to with the outstanding_lazy_seqno. With the removal of the duplication in the per-backend entry points for emitting the obsolete lazy flush, we can then further unify the engine->emit_flush. v2: Expand a bit on the legacy of gpu_caches_dirty Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Link: http://patchwork.freedesktop.org/patch/msgid/1469432687-22756-18-git-send-email-chris@chris-wilson.co.uk Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1470174640-18242-7-git-send-email-chris@chris-wilson.co.uk
2016-08-02drm/i915: Unify intel_logical_ring_emit and intel_ring_emitChris Wilson
Both perform the same actions with more or less indirection, so just unify the code. v2: Add back a few intel_engine_cs locals Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1469432687-22756-11-git-send-email-chris@chris-wilson.co.uk Link: http://patchwork.freedesktop.org/patch/msgid/1470174640-18242-1-git-send-email-chris@chris-wilson.co.uk
2016-07-21drm/i915: rename macro parameter(ring) to (engine)Dave Gordon
'ring' is an old deprecated term for a GPU engine. Here we make the terminology more consistent by renaming the 'ring' parameter of lots of macros that calculate addresses within the MMIO space of an engine. Signed-off-by: Dave Gordon <david.s.gordon@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1469034967-15840-2-git-send-email-david.s.gordon@intel.com Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
2016-07-20drm/i915: Treat ringbuffer writes as write to normal memoryChris Wilson
Ringbuffers are now being written to either through LLC or WC paths, so treating them as simply iomem is no longer adequate. However, for the older !llc hardware, the hardware is documentated as treating the TAIL register update as serialising, so we can relax the barriers when filling the rings (but even if it were not, it is still an uncached register write and so serialising anyway.). For simplicity, let's ignore the iomem annotation. v2: Remove iomem from ringbuffer->virtual_address v3: And for good measure add iomem elsewhere to keep sparse happy Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> #v2 Link: http://patchwork.freedesktop.org/patch/msgid/1469005202-9659-8-git-send-email-chris@chris-wilson.co.uk Link: http://patchwork.freedesktop.org/patch/msgid/1469017917-15134-7-git-send-email-chris@chris-wilson.co.uk
2016-07-14drm/i915: Move common engine setup into intel_engine_cs.cTvrtko Ursulin
Common code deserves to be put in a separate file from legacy and execlists implementation for clarity and ease of maintenance. Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Chris Wilson <chris-wilson.co.uk>
2016-07-14drm/i915: Unify engine init loopTvrtko Ursulin
With the unified common engine setup done, and the execlist engine initialization loop clearly split into two phases, we can eliminate the separate legacy engine initialization code. v2: Fix cleanup path for legacy. v3: Rename constructors. (Chris Wilson) Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Chris Wilson <chris-wilson.co.uk>
2016-06-17drm/i915: Introduce execlist context status change notificationZhi Wang
This patch introduces an approach to track the execlist context status change. GVT-g uses GVT context as the "shadow context". The content inside GVT context will be copied back to guest after the context is idle. And GVT-g has to know the status of the execlist context. This function is configurable when creating a new GEM context. Currently, Only GVT-g will create the "status-change-notification" enabled GEM context. v10: - Fix the identation. (Joonas) v8: - Remove the boolean flag in struct i915_gem_context. (Joonas) v7: - Remove per-engine ctx status notifiers. Use one status notifier for all engines. (Joonas) - Add prefix "INTEL_" for related definitions. (Joonas) - Refine the comments in execlists_context_status_change(). (Joonas) v6: - When !CONFIG_DRM_I915_GVT, make GVT code as dead code then compiler could automatically eliminate them for us. (Chris) - Always initialize the notifier header, so it could be switched on/off at runtime. (Chris) v5: - Only compile this feature when CONFIG_DRM_I915_GVT is enabled.(Tvrtko) Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> (v8) Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> Signed-off-by: Zhi Wang <zhi.a.wang@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1466078825-6662-8-git-send-email-zhi.a.wang@intel.com Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
2016-05-24drm/i915: Merge legacy+execlists context structsChris Wilson
struct intel_context contains two substructs, one for the legacy RCS and one for every execlists engine. Since legacy RCS is a subset of the execlists engine support, just combine the two substructs. v2: Only pin the default context for legacy mode (the object only exists for legacy, but adding i915.enable_execlists provides symmetry with the cleanup functions). Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1464098023-3294-8-git-send-email-chris@chris-wilson.co.uk
2016-05-24drm/i915: Rename struct intel_contextChris Wilson
Our goal is to rename the anonymous per-engine struct beneath the current intel_context. However, after a lively debate resolving around the confusion between intel_context_engine and intel_engine_context, the realisation is that the two structs target different users. The outer struct is API / user facing, and so carries the higher level GEM information. The inner struct is hw facing. Thus we want to name the inner struct intel_context and the outer one i915_gem_context. As the first step, we need to rename the current struct: s/struct intel_context/struct i915_gem_context/ which fits much better with its constructors already conveying the i915_gem_context prefix! Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Dave Gordon <david.s.gordon@intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1464098023-3294-1-git-send-email-chris@chris-wilson.co.uk
2016-05-09drm/i915: Store a i915 backpointer from engine, and use itChris Wilson
text data bss dec hex filename 6309351 3578714 696320 10584385 a18141 vmlinux 6308391 3578714 696320 10583425 a17d81 vmlinux Almost 1KiB of code reduction. v2: More s/INTEL_INFO()->gen/INTEL_GEN()/ and IS_GENx() conversions text data bss dec hex filename 6304579 3578778 696320 10579677 a16edd vmlinux 6303427 3578778 696320 10578525 a16a5d vmlinux Now over 1KiB! Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1462545621-30125-3-git-send-email-chris@chris-wilson.co.uk
2016-04-28drm/i915: Stop tracking execlists retired requestsTvrtko Ursulin
With the previous patch having extended the pinned lifetime of contexts by referencing the previous context from the current request until the latter is retired (completed by the GPU), we can now remove usage of execlist retired queue entirely. This is because the above now guarantees that all execlist object access requirements are satisfied by this new tracking, and we can stop taking additional references and stop keeping request on the execlists retired queue. The latter was a source of significant scalability issues in the driver causing performance hits on some tests. Most dramatical of which was igt/gem_close_race which had run time in tens of minutes which is now reduced to tens of seconds. Signed-off-by: Tvrtko Ursulin <tvrtko@ursulin.net> Cc: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Link: http://patchwork.freedesktop.org/patch/msgid/1461833819-3991-24-git-send-email-chris@chris-wilson.co.uk
2016-04-28drm/i915: Move the magical deferred context allocation into the requestChris Wilson
We can hide more details of execlists from higher level code by removing the explicit call to create an execlist context from execbuffer and into its first use by execlists. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1461833819-3991-20-git-send-email-chris@chris-wilson.co.uk
2016-04-28drm/i915: Replace the pinned context address with its unique IDChris Wilson
Rather than reuse the current location of the context in the global GTT for its hardware identifier, use the context's unique ID assigned to it for its whole lifetime. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1461833819-3991-18-git-send-email-chris@chris-wilson.co.uk
2016-04-28drm/i915: Unify intel_ring_begin()Chris Wilson
Combine the near identical implementations of intel_logical_ring_begin() and intel_ring_begin() - the only difference is that the logical wait has to check for a matching ring (which is assumed by legacy). In the process some debug messages are culled as there were following a WARN if we hit an actual error. v2: Updated commentary Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1461833819-3991-12-git-send-email-chris@chris-wilson.co.uk
2016-04-14drm/i915: Disentangle i915_drv.h includesChris Wilson
Separate out the layers of includes (linux, drm, intel, i915) so that it is a little easier to order our definitions between our multiple reentrant headers. A couple of headers needed fixes to make them more standalone (forgotten includes, forward declarations etc). Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1460565315-7748-2-git-send-email-chris@chris-wilson.co.uk
2016-04-13drm/i915: Use new i915_gem_object_pin_map for LRCTvrtko Ursulin
We can use the new pin/lazy unpin API for simplicity and more performance in the execlist submission paths. v2: * Fix error handling and convert more users. * Compact some names for readability. v3: * intel_lr_context_free was not unpinning. * Special case for GPU reset which otherwise unbalances the HWS object pages pin count by running the engine initialization only (not destructors). v4: * Rebased on top of hws setup/init split. Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Link: http://patchwork.freedesktop.org/patch/msgid/1460472042-1998-1-git-send-email-tvrtko.ursulin@linux.intel.com [tursulin: renames: s/hwd/hws/, s/obj_addr/vaddr/] Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
2016-04-12drm/i915: Only grab correct forcewake for the engine with execlistsTvrtko Ursulin
Rather than blindly waking up all forcewake domains on command submission, we can teach each engine what is (or are) the correct one to take. On platforms with multiple forcewake domains like VLV, CHV, SKL and BXT, this has the potential of lowering the GPU and CPU power use and submission latency. To implement it we add a function named intel_uncore_forcewake_for_reg whose purpose is to query which forcewake domains need to be taken to read or write a specific register with raw mmio accessors. These enables the execlists engine setup to query which forcewake domains are relevant per engine on the currently running platform. v2: * Kerneldoc. * Split from intel_uncore.c macro extraction, WARN_ON, no warns on old platforms. (Chris Wilson) v3: * Single domain per engine, mention all registers, bi-directional function and a new name, fix handling of gen6 and gen7 writes. (Chris Wilson) Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Link: http://patchwork.freedesktop.org/patch/msgid/1460468251-14069-1-git-send-email-tvrtko.ursulin@linux.intel.com
2016-04-04drm/i915: Move execlists irq handler to a bottom halfTvrtko Ursulin
Doing a lot of work in the interrupt handler introduces huge latencies to the system as a whole. Most dramatic effect can be seen by running an all engine stress test like igt/gem_exec_nop/all where, when the kernel config is lean enough, the whole system can be brought into multi-second periods of complete non-interactivty. That can look for example like this: NMI watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [kworker/u8:3:143] Modules linked in: [redacted for brevity] CPU: 0 PID: 143 Comm: kworker/u8:3 Tainted: G U L 4.5.0-160321+ #183 Hardware name: Intel Corporation Broadwell Client platform/WhiteTip Mountain 1 Workqueue: i915 gen6_pm_rps_work [i915] task: ffff8800aae88000 ti: ffff8800aae90000 task.ti: ffff8800aae90000 RIP: 0010:[<ffffffff8104a3c2>] [<ffffffff8104a3c2>] __do_softirq+0x72/0x1d0 RSP: 0000:ffff88014f403f38 EFLAGS: 00000206 RAX: ffff8800aae94000 RBX: 0000000000000000 RCX: 00000000000006e0 RDX: 0000000000000020 RSI: 0000000004208060 RDI: 0000000000215d80 RBP: ffff88014f403f80 R08: 0000000b1b42c180 R09: 0000000000000022 R10: 0000000000000004 R11: 00000000ffffffff R12: 000000000000a030 R13: 0000000000000082 R14: ffff8800aa4d0080 R15: 0000000000000082 FS: 0000000000000000(0000) GS:ffff88014f400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa53b90c000 CR3: 0000000001a0a000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: 042080601b33869f ffff8800aae94000 00000000fffc2678 ffff88010000000a 0000000000000000 000000000000a030 0000000000005302 ffff8800aa4d0080 0000000000000206 ffff88014f403f90 ffffffff8104a716 ffff88014f403fa8 Call Trace: <IRQ> [<ffffffff8104a716>] irq_exit+0x86/0x90 [<ffffffff81031e7d>] smp_apic_timer_interrupt+0x3d/0x50 [<ffffffff814f3eac>] apic_timer_interrupt+0x7c/0x90 <EOI> [<ffffffffa01c5b40>] ? gen8_write64+0x1a0/0x1a0 [i915] [<ffffffff814f2b39>] ? _raw_spin_unlock_irqrestore+0x9/0x20 [<ffffffffa01c5c44>] gen8_write32+0x104/0x1a0 [i915] [<ffffffff8132c6a2>] ? n_tty_receive_buf_common+0x372/0xae0 [<ffffffffa017cc9e>] gen6_set_rps_thresholds+0x1be/0x330 [i915] [<ffffffffa017eaf0>] gen6_set_rps+0x70/0x200 [i915] [<ffffffffa0185375>] intel_set_rps+0x25/0x30 [i915] [<ffffffffa01768fd>] gen6_pm_rps_work+0x10d/0x2e0 [i915] [<ffffffff81063852>] ? finish_task_switch+0x72/0x1c0 [<ffffffff8105ab29>] process_one_work+0x139/0x350 [<ffffffff8105b186>] worker_thread+0x126/0x490 [<ffffffff8105b060>] ? rescuer_thread+0x320/0x320 [<ffffffff8105fa64>] kthread+0xc4/0xe0 [<ffffffff8105f9a0>] ? kthread_create_on_node+0x170/0x170 [<ffffffff814f351f>] ret_from_fork+0x3f/0x70 [<ffffffff8105f9a0>] ? kthread_create_on_node+0x170/0x170 I could not explain, or find a code path, which would explain a +20 second lockup, but from some instrumentation it was apparent the interrupts off proportion of time was between 10-25% under heavy load which is quite bad. When a interrupt "cliff" is reached, which was >~320k irq/s on my machine, the whole system goes into a terrible state of the above described multi-second lockups. By moving the GT interrupt handling to a tasklet in a most simple way, the problem above disappears completely. Testing the effect on sytem-wide latencies using igt/gem_syslatency shows the following before this patch: gem_syslatency: cycles=1532739, latency mean=416531.829us max=2499237us gem_syslatency: cycles=1839434, latency mean=1458099.157us max=4998944us gem_syslatency: cycles=1432570, latency mean=2688.451us max=1201185us gem_syslatency: cycles=1533543, latency mean=416520.499us max=2498886us This shows that the unrelated process is experiencing huge delays in its wake-up latency. After the patch the results look like this: gem_syslatency: cycles=808907, latency mean=53.133us max=1640us gem_syslatency: cycles=862154, latency mean=62.778us max=2117us gem_syslatency: cycles=856039, latency mean=58.079us max=2123us gem_syslatency: cycles=841683, latency mean=56.914us max=1667us Showing a huge improvement in the unrelated process wake-up latency. It also shows an approximate halving in the number of total empty batches submitted during the test. This may not be worrying since the test puts the driver under a very unrealistic load with ncpu threads doing empty batch submission to all GPU engines each. Another benefit compared to the hard-irq handling is that now work on all engines can be dispatched in parallel since we can have up to number of CPUs active tasklets. (While previously a single hard-irq would serially dispatch on one engine after another.) More interesting scenario with regards to throughput is "gem_latency -n 100" which shows 25% better throughput and CPU usage, and 14% better dispatch latencies. I did not find any gains or regressions with Synmark2 or GLbench under light testing. More benchmarking is certainly required. v2: * execlists_lock should be taken as spin_lock_bh when queuing work from userspace now. (Chris Wilson) * uncore.lock must be taken with spin_lock_irq when submitting requests since that now runs from either softirq or process context. v3: * Expanded commit message with more testing data; * converted missed locking sites to _bh; * added execlist_lock comment. (Chris Wilson) v4: * Mention dispatch parallelism in commit. (Chris Wilson) * Do not hold uncore.lock over MMIO reads since the block is already serialised per-engine via the tasklet itself. (Chris Wilson) * intel_lrc_irq_handler should be static. (Chris Wilson) * Cancel/sync the tasklet on GPU reset. (Chris Wilson) * Document and WARN that tasklet cannot be active/pending on engine cleanup. (Chris Wilson/Imre Deak) Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Imre Deak <imre.deak@intel.com> Testcase: igt/gem_exec_nop/all Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94350 Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Link: http://patchwork.freedesktop.org/patch/msgid/1459768316-6670-1-git-send-email-tvrtko.ursulin@linux.intel.com
2016-03-16drm/i915: Rename intel_engine_cs function parametersTvrtko Ursulin
@@ identifier func; @@ func(..., struct intel_engine_cs * - ring + engine , ...) { <... - ring + engine ...> } @@ identifier func; type T; @@ T func(..., struct intel_engine_cs * - ring + engine , ...); Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
2016-01-28drm/i915: Make LRC (un)pinning work on context and engineTvrtko Ursulin
Previously intel_lr_context_(un)pin were operating on requests which is in conflict with their names. If we make them take a context and an engine, it makes the names make more sense and it also makes future fixes possible. v2: Rebase for default_context/kernel_context change. Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Nick Hoath <nicholas.hoath@intel.com>
2016-01-18drm/i915: Do not call API requiring struct_mutex where it is not availableTvrtko Ursulin
LRC code was calling GEM API like i915_gem_obj_ggtt_offset from places where the struct_mutex cannot be grabbed (irq handlers). To avoid that this patch caches some interesting bits and values in the engine and context structures. Some usages are also removed where they are not needed like a few asserts which are either impossible or have been checked already during engine initialization. Side benefit is also that interrupt handlers and command submission stop evaluating invariant conditionals, like what Gen we are running on, on every interrupt and every command submitted. This patch deals with logical ring context id and descriptors while subsequent patches will deal with the remaining issues. v2: * Cache the VMA instead of the address. (Chris Wilson) * Incorporate Dave Gordon's good comments and function name. v3: * Extract ctx descriptor template to a function and group functions dealing with ctx descriptor & co together near top of the file. (Dave Gordon) Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Dave Gordon <david.s.gordon@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1452870629-13830-1-git-send-email-tvrtko.ursulin@linux.intel.com
2016-01-07drm/i915: Cleanup some of the CSB handlingBen Widawsky
I think this patch is a worthwhile cleanup even if it might look only marginally useful. It gets more useful in upcoming patches and for handling of future GEN platforms. The only non-mechanical part of this is the removal of the extra & operation on the ring->next_context_status_buffer. This is safe because right above this, we already did a modulus operation. Signed-off-by: Ben Widawsky <benjamin.widawsky@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1452018609-10142-2-git-send-email-benjamin.widawsky@intel.com Reviewed-by: Michel Thierry <michel.thierry@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2016-01-05drm/i915/guc: Expose (intel)_lr_context_size()Dave Gordon
The GuC code needs to know the size of a logical context, so we expose get_lr_context_size(), renaming it intel_lr_context__size() to fit the naming conventions for nonstatic functions. For: VIZ-2021 Signed-off-by: Dave Gordon <david.s.gordon@intel.com> Signed-off-by: Alex Dai <yu.dai@intel.com> Reviewed-by: Dave Gordon <david.s.gordon@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1450468812-4882-2-git-send-email-yu.dai@intel.com Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-12-04Revert "drm/i915: Extend LRC pinning to cover GPU context writeback"Daniel Vetter
This reverts commit 6d65ba943a2d1e4292a07ca7ddb6c5138b9efa5d. Mika Kuoppala traced down a use-after-free crash in module unload to this commit, because ring->last_context is leaked beyond when the context gets destroyed. Mika submitted a quick fix to patch that up in the context destruction code, but that's too much of a hack. The right fix is instead for the ring to hold a full reference onto it's last context, like we do for legacy contexts. Since this is causing a regression in BAT it gets reverted before we can close this. Cc: Nick Hoath <nicholas.hoath@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Gordon <david.s.gordon@intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Alex Dai <yu.dai@intel.com> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93248 Acked-by: Mika Kuoppala <mika.kuoppala@linux.intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
2015-12-03drm/i915: Extend LRC pinning to cover GPU context writebackNick Hoath
Use the first retired request on a new context to unpin the old context. This ensures that the hw context remains bound until it has been written back to by the GPU. Now that the context is pinned until later in the request/context lifecycle, it no longer needs to be pinned from context_queue to retire_requests. This fixes an issue with GuC submission where the GPU might not have finished writing back the context before it is unpinned. This results in a GPU hang. v2: Moved the new pin to cover GuC submission (Alex Dai) Moved the new unpin to request_retire to fix coverage leak v3: Added switch to default context if freeing a still pinned context just in case the hw was actually still using it v4: Unwrapped context unpin to allow calling without a request v5: Only create a switch to idle context if the ring doesn't already have a request pending on it (Alex Dai) Rename unsaved to dirty to avoid double negatives (Dave Gordon) Changed _no_req postfix to __ prefix for consistency (Dave Gordon) Split out per engine cleanup from context_free as it was getting unwieldy Corrected locking (Dave Gordon) v6: Removed some bikeshedding (Mika Kuoppala) Added explanation of the GuC hang that this fixes (Daniel Vetter) v7: Removed extra per request pinning from ring reset code (Alex Dai) Added forced ring unpin/clean in error case in context free (Alex Dai) Signed-off-by: Nick Hoath <nicholas.hoath@intel.com> Issue: VIZ-4277 Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Gordon <david.s.gordon@intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Alex Dai <yu.dai@intel.com> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Reviewed-by: Alex Dai <yu.dai@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-11-23Merge tag 'v4.4-rc2' into drm-intel-next-queuedDaniel Vetter
Linux 4.4-rc2 Backmerge to get at commit 1b0e3a049efe471c399674fd954500ce97438d30 Author: Imre Deak <imre.deak@intel.com> Date: Thu Nov 5 23:04:11 2015 +0200 drm/i915/skl: disable display side power well support for now so that we can proplery re-eanble skl power wells in -next. Conflicts are just adjacent lines changed, except for intel_fbdev.c where we need to interleave the changs. Nothing nefarious. Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
2015-11-18drm/i915: Type safe register read/writeVille Syrjälä
Make I915_READ and I915_WRITE more type safe by wrapping the register offset in a struct. This should eliminate most of the fumbles we've had with misplaced parens. This only takes care of normal mmio registers. We could extend the idea to other register types and define each with its own struct. That way you wouldn't be able to accidentally pass the wrong thing to a specific register access function. The gpio_reg setup is probably the ugliest thing left. But I figure I'd just leave it for now, and wait for some divine inspiration to strike before making it nice. As for the generated code, it's actually a bit better sometimes. Eg. looking at i915_irq_handler(), we can see the following change: lea 0x70024(%rdx,%rax,1),%r9d mov $0x1,%edx - movslq %r9d,%r9 - mov %r9,%rsi - mov %r9,-0x58(%rbp) - callq *0xd8(%rbx) + mov %r9d,%esi + mov %r9d,-0x48(%rbp) callq *0xd8(%rbx) So previously gcc thought the register offset might be signed and decided to sign extend it, just in case. The rest appears to be mostly just minor shuffling of instructions. v2: i915_mmio_reg_{offset,equal,valid}() helpers added s/_REG/_MMIO/ in the register defines mo more switch statements left to worry about ring_emit stuff got sorted in a prep patch cmd parser, lrc context and w/a batch buildup also in prep patch vgpu stuff cleaned up and moved to a prep patch all other unrelated changes split out v3: Rebased due to BXT DSI/BLC, MOCS, etc. v4: Rebased due to churn, s/i915_mmio_reg_t/i915_reg_t/ Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Link: http://patchwork.freedesktop.org/patch/msgid/1447853606-2751-1-git-send-email-ville.syrjala@linux.intel.com
2015-11-18drm/i915: Add functions to emit register offsets to the ringVille Syrjälä
When register type safety happens, we can't just try to emit the register itself to the ring. Instead we'll need to extract the offset from it first. Add some convenience functions that will do that. v2: Convert MOCS setup too Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1446672017-24497-20-git-send-email-ville.syrjala@linux.intel.com Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
2015-10-16Merge commit '06d1ee32a4d25356a710b49d5e95dbdd68bdf505' of ↵Dave Airlie
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into drm-next Backmerge the drm-fixes pull from Linus's tree into drm-next. This is to fix some conflicts and make future pulls cleaner
2015-09-28drm/i915: Consider HW CSB write pointer before resetting the sw read pointerMichel Thierry
A previous commit resets the Context Status Buffer (CSB) read pointer in ring init commit c0a03a2e4c4e ("drm/i915: Reset CSB read pointer in ring init") This is generally correct, but this pointer is not reset after suspend/resume in some platforms (cht). In this case, the driver should read the register value instead of resetting the sw read counter to 0. Otherwise we process old events, leading to unwanted pre-emptions or something worse. But in other platforms (bdw) and also during GPU reset or power up, the CSBWP is reset to 0x7 (an invalid number), and in this case the read pointer should be set to 5 (the interrupt code will increment this counter one more time, and will start reading from CSB[0]). v2: When the CSB registers are reset, the read pointer needs to be set to 5, otherwise the first write (CSB[0]) won't be read (Mika). Replace magic numbers with GEN8_CSB_ENTRIES (6) and GEN8_CSB_PTR_MASK (0x07). Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Cc: stable@vger.kernel.org # v4.0+ Signed-off-by: Lei Shen <lei.shen@intel.com> Signed-off-by: Deepak S <deepak.s@intel.com> Signed-off-by: Michel Thierry <michel.thierry@intel.com> Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2015-09-23drm/i915: Parametrize LRC registersVille Syrjälä
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-09-14drm/i915: Split alloc from init for lrcNick Hoath
Extend init/init_hw split to context init. - Move context initialisation in to i915_gem_init_hw - Move one off initialisation for render ring to i915_gem_validate_context - Move default context initialisation to logical_ring_init Rename intel_lr_context_deferred_create to intel_lr_context_deferred_alloc, to reflect reduced functionality & alloc/init split. This patch is intended to split out the allocation of resources & initialisation to allow easier reuse of code for resume/gpu reset. v2: Removed function ptr wrapping of do_switch_context (Daniel Vetter) Left ->init_context int intel_lr_context_deferred_alloc (Daniel Vetter) Remove unnecessary init flag & ring type test. (Daniel Vetter) Improve commit message (Daniel Vetter) v3: On init/reinit, set the hw next sequence number to the sw next sequence number. This is set to 1 at driver load time. This prevents the seqno being reset on reinit (Chris Wilson) v4: Set seqno back to ~0 - 0x1000 at start-of-day, and increment by 0x100 on reset. This makes it obvious which bbs are which after a reset. (David Gordon & John Harrison) Rebase. v5: Rebase. Fixed rebase breakage. Put context pinning in separate function. Removed code churn. (Thomas Daniel) v6: Cleanup up issues introduced in v2 & v5 (Thomas Daniel) Issue: VIZ-4798 Signed-off-by: Nick Hoath <nicholas.hoath@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: John Harrison <john.c.harrison@intel.com> Cc: David Gordon <david.s.gordon@intel.com> Cc: Thomas Daniel <thomas.daniel@intel.com> Reviewed-by: Thomas Daniel <thomas.daniel@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-08-14drm/i915: Integrate GuC-based command submissionAlex Dai
GuC-based submission is mostly the same as execlist mode, up to intel_logical_ring_advance_and_submit(), where the context being dispatched would be added to the execlist queue; at this point we submit the context to the GuC backend instead. There are, however, a few other changes also required, notably: 1. Contexts must be pinned at GGTT addresses accessible by the GuC i.e. NOT in the range [0..WOPCM_SIZE), so we have to add the PIN_OFFSET_BIAS flag to the relevant GGTT-pinning calls. 2. The GuC's TLB must be invalidated after a context is pinned at a new GGTT address. 3. GuC firmware uses the one page before Ring Context as shared data. Therefore, whenever driver wants to get base address of LRC, we will offset one page for it. LRC_PPHWSP_PN is defined as the page number of LRCA. 4. In the work queue used to pass requests to the GuC, the GuC firmware requires the ring-tail-offset to be represented as an 11-bit value, expressed in QWords. Therefore, the ringbuffer size must be reduced to the representable range (4 pages). v2: Defer adding #defines until needed [Chris Wilson] Rationalise type declarations [Chris Wilson] v4: Squashed kerneldoc patch into here [Daniel Vetter] v5: Update request->tail in code common to both GuC and execlist modes. Add a private version of lr_context_update(), as sharing the execlist version leads to race conditions when the CPU and the GuC both update TAIL in the context image. Conversion of error-captured HWS page to string must account for offset from start of object to actual HWS (LRC_PPHWSP_PN). Issue: VIZ-4884 Signed-off-by: Alex Dai <yu.dai@intel.com> Signed-off-by: Dave Gordon <david.s.gordon@intel.com> Reviewed-by: Tom O'Rourke <Tom.O'Rourke@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-08-14drm/i915: Expose one LRC function for GuC submission modeDave Gordon
GuC submission is basically execlist submission, but with the GuC handling the actual writes to the ELSP and the resulting context switch interrupts. So to describe a context for submission via the GuC, we need one of the same functions used in execlist mode. This commit exposes one such function, changing its name to better describe what it does (it's related to logical ring contexts rather than to execlists per se). v2: Replaces previous "drm/i915: Move execlists defines from .c to .h" v3: Incorporates a change to one of the functions exposed here that was previously part of an internal patch, but which was omitted from the version recently committed to drm-intel-nightly: 7a01a0a drm/i915/lrc: Update PDPx registers with lri commands So we reinstate this change here. v4: Drop v3 change, update function parameters due to collision with 8ee3615 drm/i915: Convert execlists_ctx_descriptor() for requests v5: Don't expose execlists_update_context() after all. The current version is no longer compatible with GuC submission; trying to share the execlist version of this function results in both GuC and CPU updating TAIL in the context image, with bad results when they get out of step. The GuC submission path now has its own private version that just updates the ringbuffer start address, and not TAIL or PDPx. v6: Rebased Issue: VIZ-4884 Signed-off-by: Dave Gordon <david.s.gordon@intel.com> Reviewed-by: Tom O'Rourke <Tom.O'Rourke@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-07-14drm/i915: Added Programming of the MOCSPeter Antoine
This change adds the programming of the MOCS registers to the gen 9+ platforms. The set of MOCS configuration entries introduced by this patch is intended to be minimal but sufficient to cover the needs of current userspace - i.e. a good set of defaults. It is expected to be extended in the future to provide further default values or to allow userspace to redefine its private MOCS tables based on its demand for additional caching configurations. In this setup, userspace should only utilize the first N entries, higher entries are reserved for future use. It creates a fixed register set that is programmed across the different engines so that all engines have the same table. This is done as the main RCS context only holds the registers for itself and the shared L3 values. By trying to keep the registers consistent across the different engines it should make the programming for the registers consistent. v2: -'static const' for private data structures and style changes.(Matt Turner) v3: - Make the tables "slightly" more readable. (Damien Lespiau) - Updated tables fix performance regression. v4: - Code formatting. (Chris Wilson) - re-privatised mocs code. (Daniel Vetter) v5: - Changed the name of a function. (Chris Wilson) v6: - re-based - Added Mesa table entry (skylake & broxton) (Francisco Jerez) - Tidied up the readability defines (Francisco Jerez) - NUMBER of entries defines wrong. (Jim Bish) - Added comments to clear up the meaning of the tables (Jim Bish) Signed-off-by: Peter Antoine <peter.antoine@intel.com> v7 (Francisco Jerez): - Don't write L3-specific MOCS_ESC/SCC values into the e/LLC control tables. Prefix L3-specific defines consistently with L3_ and e/LLC-specific defines with LE_ to avoid this kind of confusion in the future. - Change L3CC WT define back to RESERVED (matches my hardware documentation and the original patch, probably a misunderstanding of my own previous comment). - Drop Android tables, define new minimal tables more suitable for the open source stack. - Add comment that the MOCS tables are part of the kernel ABI. - Move intel_logical_ring_begin() and _advance() calls one level down (Chris Wilson). - Minor formatting and style fixes. v8 (Francisco Jerez): - Add table size sanity check to emit_mocs_control/l3cc_table() (Chris Wilson). - Add comment about undefined entries being implicitly set to uncached for forwards compatibility. v9 (Francisco Jerez): - Minor style fixes. Signed-off-by: Francisco Jerez <currojerez@riseup.net> Acked-by: Damien Lespiau <damien.lespiau@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-07-06drm/i915: Convert intel_lr_context_pin() for requestsMika Kuoppala
Pass around requests to carry context deeper in callchain. Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-07-06drm/i915: Enable resource streamer on ExeclistsAbdiel Janulgue
GEN8 and above uses Execlists by default instead of the legacy ringbuffer for batch execution. This patch enables the resource streamer bits when required. Patch is based on the initial work by Minu Mathai <minu.mathai@intel.com> This version also adds the required bits to enable GEN8 Resource Streamer context save and restore for Execlists. Cc: ville.syrjala@linux.intel.com Signed-off-by: Abdiel Janulgue <abdiel.janulgue@linux.intel.com> Reviewed-by: Arun Siluvery <arun.siluvery@linux.intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-06-23drm/i915: Add *_ring_begin() to request allocationJohn Harrison
Now that the *_ring_begin() functions no longer call the request allocation code, it is finally safe for the request allocation code to call *_ring_begin(). This is important to guarantee that the space reserved for the subsequent i915_add_request() call does actually get reserved. v2: Renamed functions according to review feedback (Tomas Elf). For: VIZ-5115 Signed-off-by: John Harrison <John.C.Harrison@Intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-06-23drm/i915: Update flush_all_caches() to take request structuresJohn Harrison
Updated the *_ring_flush_all_caches() functions to take requests instead of rings or ringbuf/context pairs. For: VIZ-5115 Signed-off-by: John Harrison <John.C.Harrison@Intel.com> Reviewed-by: Tomas Elf <tomas.elf@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-06-23drm/i915: Merged the many do_execbuf() parameters into a structureJohn Harrison
The do_execbuf() function takes quite a few parameters. The actual set of parameters is going to change with the conversion to passing requests around. Further, it is due to grow massively with the arrival of the GPU scheduler. This patch simplifies the prototype by passing a parameter structure instead. Changing the parameter set in the future is then simply a matter of adding/removing items to the structure. Note that the structure does not contain absolutely everything that is passed in. This is because the intention is to use this structure more extensively later in this patch series and more especially in the GPU scheduler that is coming soon. The latter requires hanging on to the structure as the final hardware submission can be delayed until long after the execbuf IOCTL has returned to user land. Thus it is unsafe to put anything in the structure that is local to the IOCTL call itself - such as the 'args' parameter. All entries must be copies of data or pointers to structures that are reference counted in some way and guaranteed to exist for the duration of the batch buffer's life. v2: Rebased to newer tree and updated for changes to the command parser. Specifically, a code shuffle has required saving the batch start address in the params structure. For: VIZ-5115 Signed-off-by: John Harrison <John.C.Harrison@Intel.com> Reviewed-by: Tomas Elf <tomas.elf@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-06-23drm/i915: Set context in request from creation even in legacy modeJohn Harrison
In execlist mode, the context object pointer is written in to the request structure (and reference counted) at the point of request creation. In legacy mode, this only happens inside i915_add_request(). This patch updates the legacy code path to match the execlist version. This allows all the intermediate code between request creation and request submission to get at the context object given only a request structure. Thus negating the need to pass context pointers here, there and everywhere. v2: Moved the context reference so it does not need to be undone if the get_seqno() fails. v3: Fixed execlist mode always hitting a warning about invalid last_contexts (which don't exist in execlist mode). v4: Updated for new i915_gem_request_alloc() scheme. For: VIZ-5115 Signed-off-by: John Harrison <John.C.Harrison@Intel.com> Reviewed-by: Tomas Elf <tomas.elf@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-04-01drm/i915: Move common request allocation code into a common functionJohn Harrison
The request allocation code is largely duplicated between legacy mode and execlist mode. The actual difference between the two versions of the code is pretty minimal. This patch moves the common code out into a separate function. This is then called by the execution specific version prior to setting up the one different value. For: VIZ-5190 Signed-off-by: John Harrison <John.C.Harrison@Intel.com> Reviewed-by: Tomas Elf <tomas.elf@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-04-01drm/i915: Make intel_logical_ring_begin() staticJohn Harrison
The only usage of intel_logical_ring_begin() is within intel_lrc.c so it can be made static. To avoid a forward declaration at the top of the file, it and bunch of other functions have been shuffled upwards. For: VIZ-5115 Signed-off-by: John Harrison <John.C.Harrison@Intel.com> Reviewed-by: Tomas Elf <tomas.elf@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-02-25drm/i915: Rename 'flags' to 'dispatch_flags' for better code readingJohn Harrison
There is a flags word that is passed through the execbuffer code path all the way from initial decoding of the user parameters down to the very final dispatch buffer call. It is simply called 'flags'. Unfortuantely, there are many other flags words floating around in the same blocks of code. Even more once the GPU scheduler arrives. This patch makes it more obvious exactly which flags word is which by renaming 'flags' to 'dispatch_flags'. Note that the bit definitions for this flags word already have an 'I915_DISPATCH_' prefix on them and so are not quite so ambiguous. OTC-Jira: VIZ-1587 Signed-off-by: John Harrison <John.C.Harrison@Intel.com> [danvet: Resolve conflict with Chris' rework of the bb parsing.] Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-02-23drm/i915: Reset logical ring contexts' head and tail during GPU resetThomas Daniel
Work was getting left behind in LRC contexts during reset. This causes a hang if the GPU is reset when HEAD==TAIL because the context's ringbuffer head and tail don't get reset and retiring a request doesn't alter them, so the ring still appears full. Added a function intel_lr_context_reset() to reset head and tail on a LRC and its ringbuffer. Call intel_lr_context_reset() for each context in i915_gem_context_reset() when in execlists mode. Testcase: igt/pm_rps --run-subtest reset #bdw Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=88096 Signed-off-by: Thomas Daniel <thomas.daniel@intel.com> Reviewed-by: Dave Gordon <david.s.gordon@intel.com> [danvet: Flatten control flow in the lrc reset code a notch.] Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-02-13drm/i915: Make intel_logical_ring_advance_and_submit() staticDamien Lespiau
This function is only used in intel_lrc.c, so restrict it to that file. The function was moved around to avoid a forward declaration and group it with its user. Signed-off-by: Damien Lespiau <damien.lespiau@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-02-13drm/i915: Make intel_lr_context_render_state_init() staticDamien Lespiau
This function is only used in intel_lrc.c, so restrict it to that file. The function was moved around to avoid a forward declaration and group it with its user. Signed-off-by: Damien Lespiau <damien.lespiau@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-02-13drm/i915: Introduce bit definitions of CTXT_SR_CTRL register.Zhi Wang
This patch introduces 2 bit definitions of context save/restore control register. Signed-off-by: Zhi Wang <zhi.a.wang@intel.com> Suggested-by: Dave Gordon <david.s.gordon@intel.com> Cc: Dave Gordon <david.s.gordon@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>