- 04 May, 2020 8 commits
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Ville Syrjälä authored
Display WA #1105 says that FBC requires PLANE_STRIDE to be a multiple of 512 bytes on gen9 and glk. This is definitely true for glk as certain tests (such as igt/kms_big_fb/linear-16bpp-rotate-0) are now failing when the display resolution results in a plane stride which is not a multiple of 512 bytes. Curiously I was not able to reproduce this on a KBL. First I suspected that our use of the FBC override stride explain this, but after trying to use the override stride on glk the test still failed. I did try both the old CHICKEN_MISC_4 way and the new FBC_STRIDE way, neither had any effect on the result. Anyways, we need this at least on glk. But let's trust the spec and apply the w/a for all gen9 as well, despite being unable to reproduce the problem. v2: s/FBC_CHICKEN/FBC_STRIDE/ in commit msg Cc: José Roberto de Souza <jose.souza@intel.com> Fixes: 691f7ba5 ("drm/i915/display/fbc: Make fences a nice-to-have for GEN9+") Signed-off-by:
Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200429101034.8208-2-ville.syrjala@linux.intel.comReviewed-by:
Matt Roper <matthew.d.roper@intel.com>
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Stanislav Lisovskiy authored
That is a preparation patch before next one where we introduce old_bw_state and a bunch of other changes as well. In a review comment it was suggested to split out at least that renaming into a separate patch, what is done here. v2: Removed spurious space Reviewed-by:
Stanislav Lisovskiy <stanislav.lisovskiy@intel.com> Signed-off-by:
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Stanislav Lisovskiy authored
We need to calculate SAGV mask also in a non-modeset commit, however currently active_pipes are only calculated for modesets in global atomic state, thus now we will be tracking those also in bw_state in order to be able to properly access global data. v2: - Removed pre/post plane SAGV updates from modeset(Ville) - Now tracking active pipes in intel_can_enable_sagv(Ville) v3: - lock global state if active_pipes change as well(Ville) Signed-off-by: -
Stanislav Lisovskiy authored
Future platforms require per-crtc SAGV evaluation and serializing global state when those are changed from different commits. v2: - Add has_sagv check to intel_crtc_can_enable_sagv so that it sets bit in reject mask. - Use bw_state in intel_pre/post_plane_enable_sagv instead of atomic state v3: - Fixed rebase conflict, now using intel_atomic_crtc_state_for_each_plane_state in order to call it from atomic check v4: - Use fb modifier from plane state v5: - Make intel_has_sagv static again(Ville) - Removed unnecessary NULL assignments(Ville) - Removed unnecessary SAGV debug(Ville) - Call intel_compute_sagv_mask only for modesets(Ville) - Serialize global state only if sagv results change, but not mask itself(Ville) v6: - use lock global state instead of serialize(Ville) v7: - use both global state lock and serialize depending on if we need to change only global state or access hw (Ville) Signed-off-by: -
Chris Wilson authored
The older arches did not convert MI_STORE_DATA_IMM to using the GTT, but left them writing to a physical address. The notes suggest that the primary reason would be so that the writes were cache coherent, as the CPU cache uses physical tagging. As such we did not implement the legacy variant of MI_STORE_DATA_IMM and so left all the relocations synchronous -- but with a small function to convert from the vma address into the physical address, we can implement asynchronous relocs on these older arches, fixing up a few tests that require them. In order to be able to test the legacy paths, refactor the gpu relocations so that we can hook them up to a selftest. v2: Use an array of offsets not enum labels for the selftest v3: Refactor the common igt_hexdump() Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/757Signed-off-by:
Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by:
Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200504140629.28240-1-chris@chris-wilson.co.uk
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Chris Wilson authored
It is required that a chained batch be in the same address domain as its parent, and also that must be specified in the command for earlier gen as it is not inferred from the chaining until gen6. Fixes: 964a9b0f ("drm/i915/gem: Use chained reloc batches") Signed-off-by:
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Chris Wilson authored
Extend the timeout for pcode reads to 20ms as they should not be performed along critical paths, and succeeding after a short delay is better than failing entirely. References: https://gitlab.freedesktop.org/drm/intel/-/issues/1800Signed-off-by:
Mika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200504044903.7626-1-chris@chris-wilson.co.uk
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Chris Wilson authored
We only need the device wakeref on freeing the objects if we have to unbind the object from the global GTT, or otherwise update device information. If the objects are clean, we never need the wakeref, so avoid taking until required. Signed-off-by:
Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200503171513.18704-1-chris@chris-wilson.co.uk
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- 03 May, 2020 1 commit
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Chris Wilson authored
Currently we clear and disable the RPS pm interrupts on module load, and presume that they remain disabled forevermore. However, the mask is cleared on suspend and so after resume they may start showing up again unexepectedly. Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1811 Fixes: 8e99299a ("drm/i915/gt: Track use of RPS interrupts in flags") Signed-off-by:
Andi Shyti <andi@etezian.org> Link: https://patchwork.freedesktop.org/patch/msgid/20200502173512.32353-1-chris@chris-wilson.co.uk
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- 01 May, 2020 6 commits
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Chris Wilson authored
If at first we don't succeed, try try again. Not all engines may support the MI ops we need to perform asynchronous relocation patching, and so we end up falling back to a synchronous operation that has a liability of blocking. However, Tvrtko pointed out we don't need to use the same engine to perform the relocations as we are planning to execute the execbuf on, and so if we switch over to a working engine, we can perform the relocation asynchronously. The user execbuf will be queued after the relocations by virtue of fencing. This patch creates a new context per execbuf requiring asynchronous relocations on an unusable engines. This is perhaps a bit excessive and can be ameliorated by a small context cache, but for the moment we only need it for working around a little used engine on Sandybridge, and only if relocations are actually required to an active batch buffer. Now we just need to teach the relocation code to handle physical addressing for gen2/3, and we should then have universal support! Suggested-by:
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Chris Wilson authored
As we can now keep chaining together a relocation batch to process any number of relocations, we can keep building that relocation batch for all of the target vma. This avoiding emitting a new request into the ring for each target, consuming precious ring space and a potential stall. v2: Propagate the failure from submitting the relocation batch. Testcase: igt/gem_exec_reloc/basic-wide-active Signed-off-by:
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Chris Wilson authored
The ring is a precious resource: we anticipate to only use a few hundred bytes for a request, and only try to reserve that before we start. If we go beyond our guess in building the request, then instead of waiting at the start of execbuf before we hold any locks or other resources, we may trigger a wait inside a critical region. One example is in using gpu relocations, where currently we emit a new MI_BB_START from the ring every time we overflow a page of relocation entries. However, instead of insert the command into the precious ring, we can chain the next page of relocation entries as MI_BB_START from the end of the previous. v2: Delay the emit_bb_start until after all the chained vma synchronisation is complete. Since the buffer pool batches are idle, this _should_ be a no-op, but one day we may some fancy async GPU bindings for new vma! v3: Use pool/batch consitently, once we start thinking in terms of the batch vma, use batch->obj. v4: Explain the magic number 4. Tvrtko spotted that we lose propagation of the error for failing to submit the relocation request; that's easier to fix up in the next patch. Testcase: igt/gem_exec_reloc/basic-many-active Signed-off-by:
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Chris Wilson authored
gdb uses ptrace() to peek and poke bytes of the target's address space. The driver must implement an vm_ops->access() handler or else gdb will be unable to inspect the pointer and report it as out-of-bounds. Worse than useless as it causes immediate suspicion of the valid GTT pointer, distracting the poor programmer trying to find his bug. v2: Write-protect readonly objects (Matthew). Testcase: igt/gem_mmap_gtt/ptrace Testcase: igt/gem_mmap_offset/ptrace Suggested-by:
Kristian H. Kristensen <hoegsberg@google.com> Signed-off-by:
Matthew Auld <matthew.auld@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200501145120.18830-1-chris@chris-wilson.co.uk
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Chris Wilson authored
In order to allow userspace to rely on timeslicing to reorder their batches, we must support preemption of those user batches. Declare timeslicing as an explicit property that is a combination of having the kernel support and HW support. Suggested-by:
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Chris Wilson authored
While a perf event is open, keep a reference to the module so we don't remove the driver internals mid-sampling. Testcase: igt/perf_pmu/module-unload Signed-off-by:
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- 30 Apr, 2020 4 commits
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Chris Wilson authored
Since the introduction of 'soft-rc6', we aim to park the device quickly and that results in frequent idling of the whole device. Currently upon idling we free the batch buffer pool, and so this renders the cache ineffective for many workloads. If we want to have an effective cache of recently allocated buffers available for reuse, we need to decouple that cache from the engine powermanagement and make it timer based. As there is no reason then to keep it within the engine (where it once made retirement order easier to track), we can move it up the hierarchy to the owner of the memory allocations. v2: Hook up to debugfs/drop_caches to clear the cache on demand. Signed-off-by:
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Joonas Lahtinen authored
Signed-off-by:Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
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https://github.com/intel/gvt-linuxJoonas Lahtinen authored
gvt-next-2020-04-22 - remove non-upstream xen support bits (Christoph) - guest context shadow copy optimization (Yan) - guest context tracking for shadow skip optimization (Yan) Signed-off-by:
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Zbigniew Kempczyński authored
Extend coverage of the blitter client by exercising conversion to and from tiled sources. In the process we perform spot checks to verify that the tiling/detiling is being applied correctly, along with position invariance of the tiling parameters. Signed-off-by:
Zbigniew Kempczyński <zbigniew.kempczynski@intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Reviewed-by:
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- 29 Apr, 2020 10 commits
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Chris Wilson authored
We reduced the clocks slowly after a boost event based on the observation that the smoothness of animations suffered. However, since reducing the evalution intervals, we should be able to respond to the rapidly fluctuating workload of a simple desktop animation and so restore the more aggressive downclocking. References: 2a8862d2 ("drm/i915: Reduce the RPS shock") Signed-off-by:
Andi Shyti <andi.shyti@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200429205446.3259-6-chris@chris-wilson.co.uk
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Chris Wilson authored
We treat parking as a manual RPS timeout event, and downclock the GPU for the next unpark and batch execution. However, having restored the aggressive downclocking and observed that we have very light workloads whose only interaction is through the manual parking events, carry over the aggressive downclocking to the fake RPS events. References: 21abf0bf ("drm/i915/gt: Treat idling as a RPS downclock event") Signed-off-by:
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Chris Wilson authored
As with the realisation for soft-rc6, we respond to idling the engines within microseconds, far faster than the response times for HW RC6 and RPS. Furthermore, our fast parking upon idle, prevents HW RPS from running for many desktop workloads, as the RPS evaluation intervals are on the order of tens of milliseconds, but the typical workload is just a couple of milliseconds, but yet we still need to determine the best frequency for user latency versus power. Recognising that the HW evaluation intervals are a poor fit, and that they were deprecated [in bspec at least] from gen10, start to wean ourselves off them and replace the EI with a timer and our accurate busy-stats. The principle benefit of manually evaluating RPS intervals is that we can be more responsive for better performance and powersaving for both spiky workloads and steady-state. Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1698 Fixes: 98479ada ("drm/i915/gt: Treat idling as a RPS downclock event") Signed-off-by:
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Chris Wilson authored
Use the new intel_rps.flags field to store whether or not interrupts are being used with RPS. Signed-off-by:
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Chris Wilson authored
Pull the boolean intel_rps.enabled and intel_rps.active into a single flags field, in preparation for more. Signed-off-by:
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Chris Wilson authored
In the near future, we will utilize the busy-stats on each engine to approximate the C0 cycles of each, and use that as an input to a manual RPS mechanism. That entails having busy-stats always enabled and so we can remove the enable/disable routines and simplify the pmu setup. As a consequence of always having the stats enabled, we can also show the current active time via sysfs/engine/xcs/active_time_ns. Signed-off-by:
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Chris Wilson authored
We need to keep the default context state around to instantiate new contexts (aka golden rendercontext), and we also keep it pinned while the engine is active so that we can quickly reset a hanging context. However, the default contexts are large enough to merit keeping in swappable memory as opposed to kernel memory, so we store them inside shmemfs. Currently, we use the normal GEM objects to create the default context image, but we can throw away all but the shmemfs file. This greatly simplifies the tricky power management code which wants to run underneath the normal GT locking, and we definitely do not want to use any high level objects that may appear to recurse back into the GT. Though perhaps the primary advantage of the complex GEM object is that we aggressively cache the mapping, but here we are recreating the vm_area everytime time we unpark. At the worst, we add a lightweight cache, but first find a microbenchmark that is impacted. Having started to create some utility functions to make working with shmemfs objects easier, we can start putting them to wider use, where GEM objects are overkill, such as storing persistent error state. Signed-off-by:
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Dan Carpenter authored
If intel_context_create() fails then it leads to an error pointer dereference. I shuffled things around to make error handling easier. Fixes: 1dd47b54 ("drm/i915: Add live selftests for indirect ctx batchbuffers") Signed-off-by:
Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by:
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Chris Wilson authored
Once the intel_context is closed, the GEM context may be freed and so the link from intel_context.gem_context is invalid. <3>[ 219.782944] BUG: KASAN: use-after-free in intel_engine_coredump_alloc+0x1bc3/0x2250 [i915] <3>[ 219.782996] Read of size 8 at addr ffff8881d7dff0b8 by task kworker/0:1/12 <4>[ 219.783052] CPU: 0 PID: 12 Comm: kworker/0:1 Tainted: G U 5.7.0-rc2-g1f3ffd7683d54-kasan_118+ #1 <4>[ 219.783055] Hardware name: System manufacturer System Product Name/Z170 PRO GAMING, BIOS 3402 04/26/2017 <4>[ 219.783105] Workqueue: events heartbeat [i915] <4>[ 219.783109] Call Trace: <4>[ 219.783113] <IRQ> <4>[ 219.783119] dump_stack+0x96/0xdb <4>[ 219.783177] ? intel_engine_coredump_alloc+0x1bc3/0x2250 [i915] <4>[ 219.783182] print_address_description.constprop.6+0x16/0x310 <4>[ 219.783239] ? intel_engine_coredump_alloc+0x1bc3/0x2250 [i915] <4>[ 219.783295] ? intel_engine_coredump_alloc+0x1bc3/0x2250 [i915] <4>[ 219.783300] __kasan_report+0x137/0x190 <4>[ 219.783359] ? intel_engine_coredump_alloc+0x1bc3/0x2250 [i915] <4>[ 219.783366] kasan_report+0x32/0x50 <4>[ 219.783426] intel_engine_coredump_alloc+0x1bc3/0x2250 [i915] <4>[ 219.783481] execlists_reset+0x39c/0x13d0 [i915] <4>[ 219.783494] ? mark_held_locks+0x9e/0xe0 <4>[ 219.783546] ? execlists_hold+0xfc0/0xfc0 [i915] <4>[ 219.783551] ? lockdep_hardirqs_on+0x348/0x5f0 <4>[ 219.783557] ? _raw_spin_unlock_irqrestore+0x34/0x60 <4>[ 219.783606] ? execlists_submission_tasklet+0x118/0x3a0 [i915] <4>[ 219.783615] tasklet_action_common.isra.14+0x13b/0x410 <4>[ 219.783623] ? __do_softirq+0x1e4/0x9a7 <4>[ 219.783630] __do_softirq+0x226/0x9a7 <4>[ 219.783643] do_softirq_own_stack+0x2a/0x40 <4>[ 219.783647] </IRQ> <4>[ 219.783692] ? heartbeat+0x3e2/0x10f0 [i915] <4>[ 219.783696] do_softirq.part.13+0x49/0x50 <4>[ 219.783700] __local_bh_enable_ip+0x1a2/0x1e0 <4>[ 219.783748] heartbeat+0x409/0x10f0 [i915] <4>[ 219.783801] ? __live_idle_pulse+0x9f0/0x9f0 [i915] <4>[ 219.783806] ? lock_acquire+0x1ac/0x8a0 <4>[ 219.783811] ? process_one_work+0x811/0x1870 <4>[ 219.783827] ? rcu_read_lock_sched_held+0x9c/0xd0 <4>[ 219.783832] ? rcu_read_lock_bh_held+0xb0/0xb0 <4>[ 219.783836] ? _raw_spin_unlock_irq+0x1f/0x40 <4>[ 219.783845] process_one_work+0x8ca/0x1870 <4>[ 219.783848] ? lock_acquire+0x1ac/0x8a0 <4>[ 219.783852] ? worker_thread+0x1d0/0xb80 <4>[ 219.783864] ? pwq_dec_nr_in_flight+0x2c0/0x2c0 <4>[ 219.783870] ? do_raw_spin_lock+0x129/0x290 <4>[ 219.783886] worker_thread+0x82/0xb80 <4>[ 219.783895] ? __kthread_parkme+0xaf/0x1b0 <4>[ 219.783902] ? process_one_work+0x1870/0x1870 <4>[ 219.783906] kthread+0x34e/0x420 <4>[ 219.783911] ? kthread_create_on_node+0xc0/0xc0 <4>[ 219.783918] ret_from_fork+0x3a/0x50 <3>[ 219.783950] Allocated by task 1264: <4>[ 219.783975] save_stack+0x19/0x40 <4>[ 219.783978] __kasan_kmalloc.constprop.3+0xa0/0xd0 <4>[ 219.784029] i915_gem_create_context+0xa2/0xab8 [i915] <4>[ 219.784081] i915_gem_context_create_ioctl+0x1fa/0x450 [i915] <4>[ 219.784085] drm_ioctl_kernel+0x1d8/0x270 <4>[ 219.784088] drm_ioctl+0x676/0x930 <4>[ 219.784092] ksys_ioctl+0xb7/0xe0 <4>[ 219.784096] __x64_sys_ioctl+0x6a/0xb0 <4>[ 219.784100] do_syscall_64+0x94/0x530 <4>[ 219.784103] entry_SYSCALL_64_after_hwframe+0x49/0xb3 <3>[ 219.784120] Freed by task 12: <4>[ 219.784141] save_stack+0x19/0x40 <4>[ 219.784145] __kasan_slab_free+0x130/0x180 <4>[ 219.784148] kmem_cache_free_bulk+0x1bd/0x500 <4>[ 219.784152] kfree_rcu_work+0x1d8/0x890 <4>[ 219.784155] process_one_work+0x8ca/0x1870 <4>[ 219.784158] worker_thread+0x82/0xb80 <4>[ 219.784162] kthread+0x34e/0x420 <4>[ 219.784165] ret_from_fork+0x3a/0x50 Fixes: 2e46a2a0 ("drm/i915: Use explicit flag to mark unreachable intel_context") Signed-off-by:
Akeem G Abodunrin <akeem.g.abodunrin@intel.com> Reviewed-by:
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Nathan Chancellor authored
When building with clang + -Wuninitialized: drivers/gpu/drm/i915/gt/debugfs_gt_pm.c:407:7: warning: variable 'rpcurupei' is uninitialized when used here [-Wuninitialized] rpcurupei, ^~~~~~~~~ drivers/gpu/drm/i915/gt/debugfs_gt_pm.c:304:16: note: initialize the variable 'rpcurupei' to silence this warning u32 rpcurupei, rpcurup, rpprevup; ^ = 0 1 warning generated. rpupei is assigned twice; based on the second argument to intel_uncore_read, it seems this one should have been assigned to rpcurupei. Fixes: 9c878557 ("drm/i915/gt: Use the RPM config register to determine clk frequencies") Link: https://github.com/ClangBuiltLinux/linux/issues/1016Signed-off-by:Nathan Chancellor <natechancellor@gmail.com> Reviewed-by:
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- 28 Apr, 2020 6 commits
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Chris Wilson authored
Check that we do not submit two contexts into ELSP with the same CCID [upper portion of the descriptor]. References: https://gitlab.freedesktop.org/drm/intel/-/issues/1793Signed-off-by:
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Chris Wilson authored
The presumption is that by using a circular counter that is twice as large as the maximum ELSP submission, we would never reuse the same CCID for two inflight contexts. However, if we continually preempt an active context such that it always remains inflight, it can be resubmitted with an arbitrary number of paired contexts. As each of its paired contexts will use a new CCID, eventually it will wrap and submit two ELSP with the same CCID. Rather than use a simple circular counter, switch over to a small bitmap of inflight ids so we can avoid reusing one that is still potentially active. Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1796 Fixes: 2935ed53 ("drm/i915: Remove logical HW ID") Signed-off-by:
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Chris Wilson authored
The bspec is confusing on the nature of the upper 32bits of the LRC descriptor. Once upon a time, it said that it uses the upper 32b to decide if it should perform a lite-restore, and so we must ensure that each unique context submitted to HW is given a unique CCID [for the duration of it being on the HW]. Currently, this is achieved by using a small circular tag, and assigning every context submitted to HW a new id. However, this tag is being cleared on repinning an inflight context such that we end up re-using the 0 tag for multiple contexts. To avoid accidentally clearing the CCID in the upper 32bits of the LRC descriptor, split the descriptor into two dwords so we can update the GGTT address separately from the CCID. Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1796 Fixes: 2935ed53 ("drm/i915: Remove logical HW ID") Signed-off-by:
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Matt Atwood authored
Reflect recent Bspec changes v2: fix whitespace, typo Signed-off-by:
Matt Atwood <matthew.s.atwood@intel.com> Reviewed-by:
Radhakrishna Sripada <Radhakrishna.sripada@intel.com> Signed-off-by:
Rodrigo Vivi <rodrigo.vivi@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200415193535.14597-1-matthew.s.atwood@intel.com
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Chris Wilson authored
Give a small bump for our tolerance on comparing the expected vs measured clock ticks/time from 10% to 12.5% to accommodate a bad result on Sandybridge that was off by 10.3%. Hopefully, that is the worst we will see. Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1802Signed-off-by:
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Colin Ian King authored
There is a spelling mistaking in a pr_notice message. Fix it. Signed-off-by:
Colin Ian King <colin.king@canonical.com> Reviewed-by:
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- 27 Apr, 2020 5 commits
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Matt Roper authored
The IRQ postinstall handling had open-coded pipe fault mask selection that never got updated for gen11. Switch it to use gen8_de_pipe_fault_mask() to ensure we don't miss updates for new platforms. Cc: José Roberto de Souza <jose.souza@intel.com> Fixes: d506a65d ("drm/i915: Catch GTT fault errors for gen11+ planes") Signed-off-by:
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Chris Wilson authored
The bspec lists both the clock frequency and the effective interval. The interval corresponds to observed behaviour, so adjust the frequency to match. v2: Mika rightfully asked if we could measure the clock frequency from a selftest. Signed-off-by:
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Chris Wilson authored
We see that if the HW doesn't actually sleep, the HW may eat the poison we set in its write-only HWSP during sanitize: intel_gt_resume.part.8: 0000:00:02.0 __gt_unpark: 0000:00:02.0 gt_sanitize: 0000:00:02.0 force:yes process_csb: 0000:00:02.0 vcs0: cs-irq head=5, tail=90 process_csb: 0000:00:02.0 vcs0: csb[0]: status=0x5a5a5a5a:0x5a5a5a5a assert_pending_valid: Nothing pending for promotion! The CS TAIL pointer should have been reset by reset_csb_pointers(), so in this case it is likely that we have read back from the CPU cache and so we must clflush our control over that page. In doing so, push the sanitisation to the start of the GT sequence so that our poisoning is assuredly before we start talking to the HW. References: https://gitlab.freedesktop.org/drm/intel/-/issues/1794Signed-off-by:
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Chris Wilson authored
The hwsp_cacheline pointer from i915_request is very, very flimsy. The i915_request.timeline (and the hwsp_cacheline) are lost upon retiring (after an RCU grace). Therefore we need to confirm that once we have the right pointer for the cacheline, it is not in the process of being retired and disposed of before we attempt to acquire a reference to the cacheline. <3>[ 547.208237] BUG: KASAN: use-after-free in active_debug_hint+0x6a/0x70 [i915] <3>[ 547.208366] Read of size 8 at addr ffff88822a0d2710 by task gem_exec_parall/2536 <4>[ 547.208547] CPU: 3 PID: 2536 Comm: gem_exec_parall Tainted: G U 5.7.0-rc2-ged7a286b5d02d-kasan_117+ #1 <4>[ 547.208556] Hardware name: Dell Inc. XPS 13 9350/, BIOS 1.4.12 11/30/2016 <4>[ 547.208564] Call Trace: <4>[ 547.208579] dump_stack+0x96/0xdb <4>[ 547.208707] ? active_debug_hint+0x6a/0x70 [i915] <4>[ 547.208719] print_address_description.constprop.6+0x16/0x310 <4>[ 547.208841] ? active_debug_hint+0x6a/0x70 [i915] <4>[ 547.208963] ? active_debug_hint+0x6a/0x70 [i915] <4>[ 547.208975] __kasan_report+0x137/0x190 <4>[ 547.209106] ? active_debug_hint+0x6a/0x70 [i915] <4>[ 547.209127] kasan_report+0x32/0x50 <4>[ 547.209257] ? i915_gemfs_fini+0x40/0x40 [i915] <4>[ 547.209376] active_debug_hint+0x6a/0x70 [i915] <4>[ 547.209389] debug_print_object+0xa7/0x220 <4>[ 547.209405] ? lockdep_hardirqs_on+0x348/0x5f0 <4>[ 547.209426] debug_object_assert_init+0x297/0x430 <4>[ 547.209449] ? debug_object_free+0x360/0x360 <4>[ 547.209472] ? lock_acquire+0x1ac/0x8a0 <4>[ 547.209592] ? intel_timeline_read_hwsp+0x4f/0x840 [i915] <4>[ 547.209737] ? i915_active_acquire_if_busy+0x66/0x120 [i915] <4>[ 547.209861] i915_active_acquire_if_busy+0x66/0x120 [i915] <4>[ 547.209990] ? __live_alloc.isra.15+0xc0/0xc0 [i915] <4>[ 547.210005] ? rcu_read_lock_sched_held+0xd0/0xd0 <4>[ 547.210017] ? print_usage_bug+0x580/0x580 <4>[ 547.210153] intel_timeline_read_hwsp+0xbc/0x840 [i915] <4>[ 547.210284] __emit_semaphore_wait+0xd5/0x480 [i915] <4>[ 547.210415] ? i915_fence_get_timeline_name+0x110/0x110 [i915] <4>[ 547.210428] ? lockdep_hardirqs_on+0x348/0x5f0 <4>[ 547.210442] ? _raw_spin_unlock_irq+0x2a/0x40 <4>[ 547.210567] ? __await_execution.constprop.51+0x2e0/0x570 [i915] <4>[ 547.210706] i915_request_await_dma_fence+0x8f7/0xc70 [i915] Fixes: 85bedbf1 ("drm/i915/gt: Eliminate the trylock for reading a timeline's hwsp") Signed-off-by:
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Chris Wilson authored
We evaluate *active, which is a pointer into execlists->inflight[] during dequeue to decide how long a preempt-timeout we need to apply. However, as soon as we do the submit_ports, the HW may send its ACK interrupt causing us to promote execlists->pending[] tp execlists->inflight[], overwriting the value of *active. We know *active is only stable until we submit (as we only submit when there is no pending promotion). [ 16.102328] BUG: KCSAN: data-race in execlists_dequeue+0x1449/0x1600 [i915] [ 16.102356] [ 16.102375] race at unknown origin, with read to 0xffff8881e9500488 of 8 bytes by task 429 on cpu 1: [ 16.102780] execlists_dequeue+0x1449/0x1600 [i915] [ 16.103160] __execlists_submission_tasklet+0x48/0x60 [i915] [ 16.103540] execlists_submit_request+0x38e/0x3c0 [i915] [ 16.103940] submit_notify+0x8f/0xc0 [i915] [ 16.104308] __i915_sw_fence_complete+0x61/0x420 [i915] [ 16.104683] i915_sw_fence_complete+0x58/0x80 [i915] [ 16.105054] i915_sw_fence_commit+0x16/0x20 [i915] [ 16.105457] __i915_request_queue+0x60/0x70 [i915] [ 16.105843] i915_gem_do_execbuffer+0x2d6b/0x4230 [i915] [ 16.106227] i915_gem_execbuffer2_ioctl+0x2b0/0x580 [i915] [ 16.106257] drm_ioctl_kernel+0xe9/0x130 [ 16.106279] drm_ioctl+0x27d/0x45e [ 16.106311] ksys_ioctl+0x89/0xb0 [ 16.106336] __x64_sys_ioctl+0x42/0x60 [ 16.106370] do_syscall_64+0x6e/0x2c0 [ 16.106397] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Signed-off-by:
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