Abdiel Janulgue <abdiel.janulgue@xxxxxxxxxxxxxxx> writes: > [ text/plain ] > > > On 04/12/2016 04:51 PM, Michał Winiarski wrote: >> 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@xxxxxxxxxxxxxxx >> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> >> Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxx> >> Cc: Abdiel Janulgue <abdiel.janulgue@xxxxxxxxxxxxxxx> > > Tested-by: Abdiel Janulgue <abdiel.janulgue@xxxxxxxxxxxxxxx> Patch pushed to dinq. Thanks for patch, review and testing. -Mika > > >> Signed-off-by: Michał Winiarski <michal.winiarski@xxxxxxxxx> >> --- >> drivers/gpu/drm/i915/intel_lrc.c | 10 ++++++++-- >> 1 file changed, 8 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c >> index 0d6dc5e..30abe53 100644 >> --- a/drivers/gpu/drm/i915/intel_lrc.c >> +++ b/drivers/gpu/drm/i915/intel_lrc.c >> @@ -1945,15 +1945,18 @@ static int gen8_emit_request_render(struct drm_i915_gem_request *request) >> struct intel_ringbuffer *ringbuf = request->ringbuf; >> int ret; >> >> - ret = intel_logical_ring_begin(request, 6 + WA_TAIL_DWORDS); >> + ret = intel_logical_ring_begin(request, 8 + WA_TAIL_DWORDS); >> if (ret) >> return ret; >> >> + /* We're using qword write, seqno should be aligned to 8 bytes. */ >> + BUILD_BUG_ON(I915_GEM_HWS_INDEX & 1); >> + >> /* w/a for post sync ops following a GPGPU operation we >> * need a prior CS_STALL, which is emitted by the flush >> * following the batch. >> */ >> - intel_logical_ring_emit(ringbuf, GFX_OP_PIPE_CONTROL(5)); >> + intel_logical_ring_emit(ringbuf, GFX_OP_PIPE_CONTROL(6)); >> intel_logical_ring_emit(ringbuf, >> (PIPE_CONTROL_GLOBAL_GTT_IVB | >> PIPE_CONTROL_CS_STALL | >> @@ -1961,7 +1964,10 @@ static int gen8_emit_request_render(struct drm_i915_gem_request *request) >> intel_logical_ring_emit(ringbuf, hws_seqno_address(request->engine)); >> intel_logical_ring_emit(ringbuf, 0); >> intel_logical_ring_emit(ringbuf, i915_gem_request_get_seqno(request)); >> + /* We're thrashing one dword of HWS. */ >> + intel_logical_ring_emit(ringbuf, 0); >> intel_logical_ring_emit(ringbuf, MI_USER_INTERRUPT); >> + intel_logical_ring_emit(ringbuf, MI_NOOP); >> return intel_logical_ring_advance_and_submit(request); >> } >> >> > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/intel-gfx -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html