From 537d3b10086ffae30efbc7c66777c0a08b58d3e6 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Micha=C5=82=20Winiarski?= Date: Tue, 12 Apr 2016 15:51:55 +0200 Subject: [PATCH] drm/i915: Adjust size of PIPE_CONTROL used for gen8 render seqno write MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Cc: Mika Kuoppala Cc: Abdiel Janulgue Signed-off-by: Michał Winiarski Reviewed-by: Mika Kuoppala Reviewed-by: Chris Wilson Tested-by: Abdiel Janulgue Signed-off-by: Mika Kuoppala Link: http://patchwork.freedesktop.org/patch/msgid/1460469115-26002-1-git-send-email-michal.winiarski@intel.com (cherry picked from commit ce81a65c79d6012a384563caf76d47e28947a347) Signed-off-by: Jani Nikula --- 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 48b612d80784..5c6080fd0968 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -1913,15 +1913,18 @@ 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 | @@ -1929,7 +1932,10 @@ static int gen8_emit_request_render(struct drm_i915_gem_request *request) intel_logical_ring_emit(ringbuf, hws_seqno_address(request->ring)); 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); }