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path: root/drivers/gpu/drm/i915/intel_lrc.c
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2016-07-01drm/i915: Move the get/put irq locking into the callerChris Wilson
With only a single callsite for intel_engine_cs->irq_get and ->irq_put, we can reduce the code size by moving the common preamble into the caller, and we can also eliminate the reference counting. For completeness, as we are no longer doing reference counting on irq, rename the get/put vfunctions to enable/disable respectively and are able to review the use of posting reads. We only require the serialisation with hardware when enabling the interrupt (i.e. so we cannot miss an interrupt by going to sleep before the hardware truly enables it). Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Link: http://patchwork.freedesktop.org/patch/msgid/1467390209-3576-18-git-send-email-chris@chris-wilson.co.uk
2016-07-01drm/i915: Refactor scratch object allocation for gen2 w/a bufferChris Wilson
The gen2 w/a buffer is stuffed into the same slot as the gen5+ scratch buffer. If we pass in the size we want to allocate for the scratch buffer, both callers can use the same routine. 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/1467390209-3576-11-git-send-email-chris@chris-wilson.co.uk
2016-07-01drm/i915: Use HWS for seqno tracking everywhereChris Wilson
By using the same address for storing the HWS on every platform, we can remove the platform specific vfuncs and reduce the get-seqno routine to a single read of a cached memory location. v2: Fix semaphore_passed() to look at the signaling engine (not the waiter's) 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/1467390209-3576-8-git-send-email-chris@chris-wilson.co.uk
2016-07-01drm/i915: Slaughter the thundering i915_wait_request herdChris Wilson
One particularly stressful scenario consists of many independent tasks all competing for GPU time and waiting upon the results (e.g. realtime transcoding of many, many streams). One bottleneck in particular is that each client waits on its own results, but every client is woken up after every batchbuffer - hence the thunder of hooves as then every client must do its heavyweight dance to read a coherent seqno to see if it is the lucky one. Ideally, we only want one client to wake up after the interrupt and check its request for completion. Since the requests must retire in order, we can select the first client on the oldest request to be woken. Once that client has completed his wait, we can then wake up the next client and so on. However, all clients then incur latency as every process in the chain may be delayed for scheduling - this may also then cause some priority inversion. To reduce the latency, when a client is added or removed from the list, we scan the tree for completed seqno and wake up all the completed waiters in parallel. Using igt/benchmarks/gem_latency, we can demonstrate this effect. The benchmark measures the number of GPU cycles between completion of a batch and the client waking up from a call to wait-ioctl. With many concurrent waiters, with each on a different request, we observe that the wakeup latency before the patch scales nearly linearly with the number of waiters (before external factors kick in making the scaling much worse). After applying the patch, we can see that only the single waiter for the request is being woken up, providing a constant wakeup latency for every operation. However, the situation is not quite as rosy for many waiters on the same request, though to the best of my knowledge this is much less likely in practice. Here, we can observe that the concurrent waiters incur extra latency from being woken up by the solitary bottom-half, rather than directly by the interrupt. This appears to be scheduler induced (having discounted adverse effects from having a rbtree walk/erase in the wakeup path), each additional wake_up_process() costs approximately 1us on big core. Another effect of performing the secondary wakeups from the first bottom-half is the incurred delay this imposes on high priority threads - rather than immediately returning to userspace and leaving the interrupt handler to wake the others. To offset the delay incurred with additional waiters on a request, we could use a hybrid scheme that did a quick read in the interrupt handler and dequeued all the completed waiters (incurring the overhead in the interrupt handler, not the best plan either as we then incur GPU submission latency) but we would still have to wake up the bottom-half every time to do the heavyweight slow read. Or we could only kick the waiters on the seqno with the same priority as the current task (i.e. in the realtime waiter scenario, only it is woken up immediately by the interrupt and simply queues the next waiter before returning to userspace, minimising its delay at the expense of the chain, and also reducing contention on its scheduler runqueue). This is effective at avoid long pauses in the interrupt handler and at avoiding the extra latency in realtime/high-priority waiters. v2: Convert from a kworker per engine into a dedicated kthread for the bottom-half. v3: Rename request members and tweak comments. v4: Use a per-engine spinlock in the breadcrumbs bottom-half. v5: Fix race in locklessly checking waiter status and kicking the task on adding a new waiter. v6: Fix deciding when to force the timer to hide missing interrupts. v7: Move the bottom-half from the kthread to the first client process. v8: Reword a few comments v9: Break the busy loop when the interrupt is unmasked or has fired. v10: Comments, unnecessary churn, better debugging from Tvrtko v11: Wake all completed waiters on removing the current bottom-half to reduce the latency of waking up a herd of clients all waiting on the same request. v12: Rearrange missed-interrupt fault injection so that it works with igt/drv_missed_irq_hang v13: Rename intel_breadcrumb and friends to intel_wait in preparation for signal handling. v14: RCU commentary, assert_spin_locked v15: Hide BUG_ON behind the compiler; report on gem_latency findings. v16: Sort seqno-groups by priority so that first-waiter has the highest task priority (and so avoid priority inversion). v17: Add waiters to post-mortem GPU hang state. v18: Return early for a completed wait after acquiring the spinlock. Avoids adding ourselves to the tree if the is already complete, and skips the awkward question of why we don't do completion wakeups for waits earlier than or equal to ourselves. v19: Prepare for init_breadcrumbs to fail. Later patches may want to allocate during init, so be prepared to propagate back the error code. Testcase: igt/gem_concurrent_blit Testcase: igt/benchmarks/gem_latency Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: "Rogozhkin, Dmitry V" <dmitry.v.rogozhkin@intel.com> Cc: "Gong, Zhipeng" <zhipeng.gong@intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> Cc: Dave Gordon <david.s.gordon@intel.com> Cc: "Goel, Akash" <akash.goel@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> #v18 Link: http://patchwork.freedesktop.org/patch/msgid/1467390209-3576-6-git-send-email-chris@chris-wilson.co.uk
2016-06-30drm/i915: Convert wait_for(I915_READ(reg)) to intel_wait_for_register()Chris Wilson
By using the out-of-line intel_wait_for_register() not only do we can efficiency from using the hybrid wait_for() contained within, but we avoid code bloat from the numerous inlined loops, in total (all patches): text data bss dec hex filename 1078551 4557 416 1083524 108884 drivers/gpu/drm/i915/i915.ko 1070775 4557 416 1075748 106a24 drivers/gpu/drm/i915/i915.ko 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/1467297225-21379-40-git-send-email-chris@chris-wilson.co.uk
2016-06-24drm/i915: Small compaction of the engine init codeTvrtko Ursulin
Effectively removes one layer of indirection between the mask of possible engines and the engine constructors. Instead of spelling out in code the mapping of HAS_<engine> to constructors, makes more use of the recently added data driven approach by putting engine constructor vfuncs into the table as well. Effect is fewer lines of source and smaller binary. At the same time simplify the error handling since engine destructors can run on unitialized engines anyway. Similar approach could be done for legacy submission is wanted. v2: Removed ugly BUILD_BUG_ONs in favour of newly introduced ENGINE_MASK and HAS_ENGINE macros. Also removed the forward declarations by shuffling functions around. v3: Warn when logical_rings table does not contain enough data and disable the engines which could not be initialized. (Chris Wilson) v4: Chris Wilson suggested a nicer engine init loop. 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/1466689961-23232-1-git-send-email-tvrtko.ursulin@linux.intel.com
2016-06-17drm/i915: Support LRC context single submissionZhi Wang
This patch introduces the support of LRC context single submission. As GVT context may come from different guests, which require different configuration of render registers. It can't be combined into a dual ELSP submission combo. Only GVT-g will create this kinds of GEM context currently. v8: - Rename the data member in struct i915_gem_context. (Chris) v7: - Fix typos in commit message. (Joonas) v6: - Make GVT code as dead code when !CONFIG_DRM_I915_GVT. (Chris) v5: - Only compile this feature when CONFIG_DRM_I915_GVT=y. (Tvrtko) Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> 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> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Link: http://patchwork.freedesktop.org/patch/msgid/1466078825-6662-9-git-send-email-zhi.a.wang@intel.com
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>
2016-06-17drm/i915: Make addressing mode bits in context descriptor configurableZhi Wang
Currently the addressing mode bit in context descriptor is statically generated from the configuration of system-wide PPGTT usage model. GVT-g will load the PPGTT shadow page table by itself and probably one guest is using a different addressing mode with i915 host. The addressing mode bits of a LRC context should be configurable under this case. v10: - Fix the identation. (Joonas) v9: - Rename the data member in struct i915_gem_context. (Chris) v8: - Rename the data member in struct i915_gem_context. (Chris) v7: - Move context addressing mode bit into i915_reg.h. (Joonas/Chris) - Add prefix "INTEL_" for related definitions. (Joonas) v6: - Directly save the addressing mode bits inside i915_gem_context. (Chris) - Move the LRC context addressing mode bits into intel_lrc.h. (Chris) v5: - Change USES_FULL_48BIT(dev) to USES_FULL_48BIT(dev_priv) (Tvrtko) Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> (v9) 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> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Link: http://patchwork.freedesktop.org/patch/msgid/1466078825-6662-7-git-send-email-zhi.a.wang@intel.com
2016-06-17drm/i915: Make ring buffer size of a LRC context configurableZhi Wang
This patch introduces an option for configuring the ring buffer size of a LRC context after the context creation. v9: - Fix an identation issue. (Chris) v8: - Rename the data member in i915_gem_context. (Chris) Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Zhi Wang <zhi.a.wang@intel.com> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Link: http://patchwork.freedesktop.org/patch/msgid/1466078825-6662-6-git-send-email-zhi.a.wang@intel.com
2016-06-08drm/i915/kbl: Add WaClearSlmSpaceAtContextSwitchMika Kuoppala
This workaround for bdw and chv, is also needed for kbl A0. References: HSD#1911519, BSID#569 Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1465309159-30531-24-git-send-email-mika.kuoppala@intel.com
2016-06-08drm/i915/kbl: Add WaForGAMHangMika Kuoppala
Add this workaround for A0 and B0 revisions References: HSD#2226935 Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1465309159-30531-19-git-send-email-mika.kuoppala@intel.com
2016-06-08drm/i915/kbl: Add WaDisableLSQCROPERFforOCLMika Kuoppala
Extend the scope of this workaround, already used in skl, to also take effect in kbl. v2: Fix KBL_REVID_E0 (Matthew) References: HSD#2132677 Cc: Matthew Auld <matthew.william.auld@gmail.com> Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1465309159-30531-12-git-send-email-mika.kuoppala@intel.com
2016-06-06drm/i915: Fix a buch of kerneldoc warningsTvrtko Ursulin
Just a bunch of stale kerneldocs generating warnings when building the docs. Mostly function parameters so not very useful but still. v2: Tidy. Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1464958937-23344-1-git-send-email-tvrtko.ursulin@linux.intel.com
2016-05-25drm/i915: Revert async unpin and nonblocking atomic commitDaniel Vetter
This reverts the following patches: d55dbd06bb5e1399aba9ab5227465339d1bbefff drm/i915: Allow nonblocking update of pageflips. 15c86bdb760185e871c7a0f559978328aa500971 drm/i915: Check for unpin correctness. 95c2ccdc82d520f59ae3b6fdc097b63c9b7082bb Reapply "drm/i915: Avoid stalling on pending flips for legacy cursor updates" a6747b7304a9d66758a196d885dab8bbfa5e7d1f drm/i915: Make unpin async. 03f476e1fcb42fca88fc50b94b0d3adbdbe887f0 drm/i915: Prepare connectors for nonblocking checks. 2099deffef4404f949ba1b68d2b17e0608190bc2 drm/i915: Pass atomic states to fbc update functions. ee7171af72c39c18b7d7571419a4ac6ca30aea66 drm/i915: Remove reset_counter from intel_crtc. 2ee004f7c59b2e642f0bb2834f847d756f2dd7b7 drm/i915: Remove queue_flip pointer. b8d2afae557dbb9b9c7bc6f6ec4f5278f3c4c34e drm/i915: Remove use_mmio_flip kernel parameter. 8dd634d922615ec3a9af7976029110ec037f8b50 drm/i915: Remove cs based page flip support. 143f73b3bf48c089b40f58462dd7f7c199fd4f0f drm/i915: Rework intel_crtc_page_flip to be almost atomic, v3. 84fc494b64e8c591be446a966b7447a9db519c88 drm/i915: Add the exclusive fence to plane_state. 6885843ae164e11f6c802209d06921e678a3f3f3 drm/i915: Convert flip_work to a list. aa420ddd8eeaa5df579894a412289e4d07c2fee9 drm/i915: Allow mmio updates on all platforms, v2. afee4d8707ab1f21b7668de995be3a5961e83582 Revert "drm/i915: Avoid stalling on pending flips for legacy cursor updates" "drm/i915: Allow nonblocking update of pageflips" should have been split up, misses a proper commit message and seems to cause issues in the legacy page_flip path as demonstrated by kms_flip. "drm/i915: Make unpin async" doesn't handle the unthrottled cursor updates correctly, leading to an apparent pin count leak. This is caught by the WARN_ON in i915_gem_object_do_pin which screams if we have more than DRM_I915_GEM_OBJECT_MAX_PIN_COUNT pins. Unfortuantely we can't just revert these two because this patch series came with a built-in bisect breakage in the form of temporarily removing the unthrottled cursor update hack for legacy cursor ioctl. Therefore there's no other option than to revert the entire pile :( There's one tiny conflict in intel_drv.h due to other patches, nothing serious. Normally I'd wait a bit longer with doing a maintainer revert, but since the minimal set of patches we need to revert (due to the bisect breakage) is so big, time is running out fast. And very soon (especially after a few attempts at fixing issues) it'll be really hard to revert things cleanly. Lessons learned: - Not a good idea to rush the review (done by someone fairly new to the area) and not make sure domain experts had a chance to read it. - Patches should be properly split up. I only looked at the two patches that should be reverted in detail, but both look like the mix up different things in one patch. - Patches really should have proper commit messages. Especially when doing more than one thing, and especially when touching critical and tricky core code. - Building a patch series and r-b stamping it when it has a built-in bisect breakage is not a good idea. - I also think we need to stop building up technical debt by postponing atomic igt testcases even longer. I think it's clear that there's enough corner cases in this beast that we really need to have the testcases _before_ the next step lands. Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Patrik Jakobsson <patrik.jakobsson@linux.intel.com> Cc: John Harrison <John.C.Harrison@Intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Acked-by: Dave Airlie <airlied@redhat.com> Acked-by: Jani Nikula <jani.nikula@linux.intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
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: Name the inner most per-engine intel_context structChris Wilson
We want to give a name to the currently anonymous per-engine struct inside the context, so that we can assign it to a local variable and save clumsy typing. The name we have chosen is intel_context as it reflects the HW facing portion of the context state (the logical context state, the registers, the ringbuffer etc). 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/1464098023-3294-4-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
2016-05-23drm/i915/guc: pass request (not client) to i915_guc_{wq_check_space, submit}()Dave Gordon
The knowledge of how to derive the relevant client from the request should be localised within i915_guc_submission.c; the LRC code shouldn't have to know about the internal details of the GuC submission process. And all the information the GuC code needs should be encapsulated in (or reachable from) the request. v2: GEM_BUG_ON() for bad GuC client (Tvrtko Ursulin). Add/update kerneldoc explaining check_space/submit protocol Signed-off-by: Dave Gordon <david.s.gordon@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
2016-05-19drm/i915: Remove use_mmio_flip kernel parameter.Maarten Lankhorst
With the removal of cs flips this is always force enabled. Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1463490484-19540-14-git-send-email-maarten.lankhorst@linux.intel.com Reviewed-by: Patrik Jakobsson <patrik.jakobsson@linux.intel.com>
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
2016-05-09drm/i915/execlists: Refactor common engine setupChris Wilson
Move all of the constant assignments up front and into a common function. This is primarily to ensure the backpointers are set as early as possible for later use during initialisation. v2: Use a constant struct so that all the similar values are set together. v3: Sanitize the engine's IMR to disable any potential interrupt before we are ready (enabled in init_hw). v4: Ignore the engine's IMR, to be resolved later Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> Cc: Dave Gordon <david.s.gordon@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1462545621-30125-2-git-send-email-chris@chris-wilson.co.uk
2016-04-29drm/i915: Fix ordering of sanitize ppgtt and sanitize execlistsChris Wilson
The i915.enable_ppgtt option depends upon the state of i915.enable_execlists option - so we need to sanitize execlists first. 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/1461932305-14637-2-git-send-email-chris@chris-wilson.co.uk
2016-04-29drm/i915: Apply strongly ordered RCS breadcrumb to gen8/legacyChris Wilson
For legacy ringbuffer mode, we need the new ordered breadcrumb emission tried and tested on execlists in order to avoid the dreaded "missed interrupt" syndrome. A secondary advantage of the execlists method is that it writes to an arbitrary address, useful if one wants to write a breadcrumb elsewhere. This fix is taken from commit 7c17d377374dd (drm/i915: Use ordered seqno write interrupt generation on gen8+ execlists). Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@intel.com> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1461932305-14637-1-git-send-email-chris@chris-wilson.co.uk
2016-04-29drm/i915: Trim the flush for the execlists request emissionChris Wilson
At the start of request emission, we flush some space for the request, estimating the typical size for the request body. The common tail is now much larger than the typical body, so we can shrink the flush substantially. 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/1461917226-9132-3-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: Store LRC hardware id in the requestTvrtko Ursulin
This way in the following patch we can disconnect requests from contexts. Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> 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/1461833819-3991-23-git-send-email-chris@chris-wilson.co.uk
2016-04-28drm/i915: Track the previous pinned context inside the requestChris Wilson
As the contexts are accessed by the hardware until the switch is completed to a new context, the hardware may still be writing to the context object after the breadcrumb is visible. We must not unpin/unbind/prune that object whilst still active and so we keep the previous context pinned until the following request. We can generalise the tracking we already do via the engine->last_context and move it to the request so that it works equally for execlists and GuC. v2: Drop the execlists double pin as that exposes a race inside the lrc irq handler as it tries to access the context after it may be retired. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1461833819-3991-22-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: Refactor execlists default context pinningChris Wilson
Refactor pinning and unpinning of contexts, such that the default context for an engine is pinned during initialisation and unpinned during teardown (pinning of the context handles the reference counting). Thus we can eliminate the special case handling of the default context that was required to mask that it was not being pinned normally. v2: Rebalance context_queue after rebasing. v3: Rebase to -nightly (not 40 patches in) v4: Rebase onto request_alloc unwinding 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> Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1461833819-3991-19-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: Update execlists context descriptor format commentaryChris Wilson
The comments describing the Context Descriptor Format are off by a bit for the size of the context ID. 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/1461833819-3991-16-git-send-email-chris@chris-wilson.co.uk
2016-04-28drm/i915: Preallocate enough space for the average requestChris Wilson
Rather than being interrupted when we run out of space halfway through the request, and having to restart from the beginning (and returning to userspace), flush a little more free space when we prepare the request. 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/1461833819-3991-15-git-send-email-chris@chris-wilson.co.uk
2016-04-28drm/i915: Manually unwind after a failed request allocationChris Wilson
In the next patches, we want to move the work out of freeing the request and into its retirement (so that we can free the request without requiring the struct_mutex). This means that we cannot rely on unreferencing the request to completely teardown the request any more and so we need to manually unwind the failed allocation. In doing so, we reorder the allocation in order to make the unwind simple (and ensure that we don't try to unwind a partial request that may have modified global state) and so we end up pushing the initial preallocation down into the engine request initialisation functions where we have the requisite control over the state of the request. Moving the initial preallocation into the engine is less than ideal: it moves logic to handle a specific problem with request handling out of the common code. On the other hand, it does allow those backends significantly more flexibility in performing its allocations. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1461833819-3991-14-git-send-email-chris@chris-wilson.co.uk
2016-04-28drm/i915: Remove the identical implementations of request space reservationChris Wilson
Now that we share intel_ring_begin(), reserving space for the tail of the request is identical between legacy/execlists and so the tautology can be removed. In the process, we move the reserved space tracking from the ringbuffer on to the request. This is to enable us to reorder the reserved space allocation in the next patch. 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/1461833819-3991-13-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
2016-04-28drm/i915: Propagate error from drm_gem_object_init()Chris Wilson
Propagate the real error from drm_gem_object_init(). Note this also fixes some confusion in the error return from i915_gem_alloc_object... v2: (Matthew Auld) - updated new users of gem_alloc_object from latest drm-nightly - replaced occurrences of IS_ERR_OR_NULL() with IS_ERR() v3: (Joonas Lahtinen) - fix double "From:" in commit message - add goto teardown path v4: (Matthew Auld) - rebase with i915_gem_alloc_object name change Signed-off-by: Matthew Auld <matthew.auld@intel.com> 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/1461587533-8841-1-git-send-email-matthew.auld@intel.com [Joonas: Removed spurious " = NULL" from _init() function] Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
2016-04-25drm/i915: rename i915_gem_alloc_object() to i915_gem_object_create()Dave Gordon
Because having both i915_gem_object_alloc() and i915_gem_alloc_object() (with different return conventions) is just too confusing! (i915_gem_object_alloc() is the low-level memory allocator, and remains unchanged, whereas i915_gem_alloc_object() is a constructor that ALSO initialises the newly-allocated object.) Signed-off-by: Dave Gordon <david.s.gordon@intel.com> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1461348872-4702-1-git-send-email-david.s.gordon@intel.com
2016-04-20drm/i915: Remove a couple pointless WARN_ONsTvrtko Ursulin
Just two WARN_ONs followed by pointer dereference I spotted by accident. v2: Remove some more of the same. Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Link: http://patchwork.freedesktop.org/patch/msgid/1461080770-14693-1-git-send-email-tvrtko.ursulin@linux.intel.com
2016-04-14drm/i915/mocs: Program MOCS for all engines on initPeter Antoine
Allow for the MOCS to be programmed for all engines. Currently we program the MOCS when the first render batch goes through. This works on most platforms but fails on platforms that do not run a render batch early, i.e. headless servers. The patch now programs all initialised engines on init and the RCS is programmed again within the initial batch. This is done for predictable consistency with regards to the hardware context. Hardware context loading sets the values of the MOCS for RCS and L3CC. Programming them from within the batch makes sure that the render context is valid, no matter what the previous state of the saved-context was. v2: posted correct version to the mailing list. v3: moved programming to within engine->init_hw() (Chris Wilson) v4: code formatting and white-space changes. (Chris Wilson) Testcase: igt/gem_mocs_settings Signed-off-by: Peter Antoine <peter.antoine@intel.com> 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/1460556205-6644-1-git-send-email-chris@chris-wilson.co.uk
2016-04-14drm/i915: Late request cancellations are harmfulChris Wilson
Conceptually, each request is a record of a hardware transaction - we build up a list of pending commands and then either commit them to hardware, or cancel them. However, whilst building up the list of pending commands, we may modify state outside of the request and make references to the pending request. If we do so and then cancel that request, external objects then point to the deleted request leading to both graphical and memory corruption. The easiest example is to consider object/VMA tracking. When we mark an object as active in a request, we store a pointer to this, the most recent request, in the object. Then we want to free that object, we wait for the most recent request to be idle before proceeding (otherwise the hardware will write to pages now owned by the system, or we will attempt to read from those pages before the hardware is finished writing). If the request was cancelled instead, that wait completes immediately. As a result, all requests must be committed and not cancelled if the external state is unknown. All that remains of i915_gem_request_cancel() users are just a couple of extremely unlikely allocation failures, so remove the API entirely. A consequence of committing all incomplete requests is that we generate excess breadcrumbs and fill the ring much more often with dummy work. We have completely undone the outstanding_last_seqno optimisation. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93907 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> Cc: stable@vger.kernel.org Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1460565315-7748-16-git-send-email-chris@chris-wilson.co.uk
2016-04-14drm/i915: Prevent leaking of -EIO from i915_wait_request()Chris Wilson
Reporting -EIO from i915_wait_request() has proven very troublematic over the years, with numerous hard-to-reproduce bugs cropping up in the corner case of where a reset occurs and the code wasn't expecting such an error. If the we reset the GPU or have detected a hang and wish to reset the GPU, the request is forcibly complete and the wait broken. Currently, we report either -EAGAIN or -EIO in order for the caller to retreat and restart the wait (if appropriate) after dropping and then reacquiring the struct_mutex (essential to allow the GPU reset to proceed). However, if we take the view that the request is complete (no further work will be done on it by the GPU because it is dead and soon to be reset), then we can proceed with the task at hand and then drop the struct_mutex allowing the reset to occur. This transfers the burden of checking whether it is safe to proceed to the caller, which in all but one instance it is safe - completely eliminating the source of all spurious -EIO. Of note, we only have two API entry points where we expect that userspace can observe an EIO. First is when submitting an execbuf, if the GPU is terminally wedged, then the operation cannot succeed and an -EIO is reported. Secondly, existing userspace uses the throttle ioctl to detect an already wedged GPU before starting using HW acceleration (or to confirm that the GPU is wedged after an error condition). So if the GPU is wedged when the user calls throttle, also report -EIO. v2: Split more carefully the change to i915_wait_request() and assorted ABI from the reset handling. v3: Add a couple of WARN_ON(EIO) to the interruptible modesetting code so that we don't start to leak EIO there in future (and break our hang resistant modesetting). Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1460565315-7748-9-git-send-email-chris@chris-wilson.co.uk Link: http://patchwork.freedesktop.org/patch/msgid/1460565315-7748-1-git-send-email-chris@chris-wilson.co.uk
2016-04-14drm/i915: Store the reset counter when constructing a requestChris Wilson
As the request is only valid during the same global reset epoch, we can record the current reset_counter when constructing the request and reuse it when waiting upon that request in future. This removes a very hairy atomic check serialised by the struct_mutex at the time of waiting and allows us to transfer those waits to a central dispatcher for all waiters and all requests. PS: With per-engine resets, we obviously cannot assume a global reset epoch for the requests - a per-engine epoch makes the most sense. The challenge then is how to handle checking in the waiter for when to break the wait, as the fine-grained reset may also want to requeue the request (i.e. the assumption that just because the epoch changes the request is completed may be broken - or we just avoid breaking that assumption with the fine-grained resets). Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1460565315-7748-7-git-send-email-chris@chris-wilson.co.uk
2016-04-14drm/i915: Hide the atomic_read(reset_counter) behind a helperChris Wilson
This is principally a little bit of syntatic sugar to hide the atomic_read()s throughout the code to retrieve the current reset_counter. It also provides the other utility functions to check the reset state on the already read reset_counter, so that (in later patches) we can read it once and do multiple tests rather than risk the value changing between tests. v2: Be more strict on converting existing i915_reset_in_progress() over to the more verbose i915_reset_in_progress_or_wedged(). Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1460565315-7748-4-git-send-email-chris@chris-wilson.co.uk
2016-04-13drm/i915: Adjust size of PIPE_CONTROL used for gen8 render seqno writeMichał Winiarski
We started to use PIPE_CONTROL to write render ring seqno in order to combat seqno write vs interrupt generation problems. This was introduced by commit 7c17d377374d ("drm/i915: Use ordered seqno write interrupt generation on gen8+ execlists"). On gen8+ size of PIPE_CONTROL with Post Sync Operation should be 6 dwords. When we're using older 5-dword variant it's possible to observe inconsistent values written by PIPE_CONTROL with Post Sync Operation from user batches, resulting in rendering corruptions. v2: Fix BAT failures v3: Comments on alignment and thrashing high dword of seqno (Chris) v4: Updated commit msg (Mika) Testcase: igt/gem_pipe_control_store_loop/*-qword-write Issue: VIZ-7393 Cc: stable@vger.kernel.org Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@intel.com> Cc: Abdiel Janulgue <abdiel.janulgue@linux.intel.com> Signed-off-by: Michał Winiarski <michal.winiarski@intel.com> Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Tested-by: Abdiel Janulgue <abdiel.janulgue@linux.intel.com> Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1460469115-26002-1-git-send-email-michal.winiarski@intel.com
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>
2016-04-13drm/i915: Split execlists hardware status page initialisation from setupTvrtko Ursulin
Split the hardware status page into setup and initialisation, where setup means setting up the driver state to support the engine, and initialization means programming the hardware with the before set up state. This way the design matches the design of the engine setup/init code which is split in the same fashion and it enables the stages to be used in a balanced fashion (engine setup - hws setup, engine init - hws init). This will enable the upcoming improvements to slot in without any kludges on the GPU reset path. Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Suggested-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Chris Wilson <chris@chris-wilson.co.uk> 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
2016-04-11drm/i915: implement WaClearTdlStateAckDirtyBitsTim Gore
This is to fix a GPU hang seen with mid thread pre-emption and pooled EUs. v2. Use IS_BXT_REVID instead of IS_BROXTON and INTEL_REVID v3. And use correct type for register addresses Signed-off-by: Tim Gore <tim.gore@intel.com> Reviewed-by: Arun Siluvery <arun.siluvery@linux.intel.com> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1458571049-854-1-git-send-email-tim.gore@intel.com
2016-04-09drm/i915: Separate out the seqno-barrier from engine->get_seqnoChris Wilson
In order to simplify future patches, extract the lazy_coherency optimisation our of the engine->get_seqno() vfunc into its own callback. v2: Rename the barrier to engine->irq_seqno_barrier to try and better reflect that the barrier is only required after the user interrupt before reading the seqno (to ensure that the seqno update lands in time as we do not have strict seqno-irq ordering on all platforms). Reviewed-by: Dave Gordon <david.s.gordon@intel.com> [#v2] v3: Comments for hangcheck paranoia. Mika wanted to keep the extra barrier inside the hangcheck, just in case. I can argue that it doesn't provide a barrier against anything, but the side-effects of applying the barrier may prevent a false declaration of a hung GPU. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@intel.com> Cc: Dave Gordon <david.s.gordon@intel.com> Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1460195877-20520-2-git-send-email-chris@chris-wilson.co.uk