This is a required workarounds for all products, especially on gen6+ where it causes the command streamer to fail to parse instructions following a WAIT_FOR_EVENT. We use WAIT_FOR_EVENT for synchronising between the GPU and the display engines, and so this bit being unset may cause hangs.
References: https://bugzilla.kernel.org/show_bug.cgi?id=52311 Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk> Cc: sta...@vger.kernel.org --- drivers/gpu/drm/i915/i915_reg.h | 1 + drivers/gpu/drm/i915/intel_ringbuffer.c | 19 +++++++++++++------ 2 files changed, 14 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 8b81052..db1c034 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -536,6 +536,7 @@ #define MI_MODE 0x0209c # define VS_TIMER_DISPATCH (1 << 6) # define MI_FLUSH_ENABLE (1 << 12) +# define ASYNC_FLIP_PERF_DISABLE (1 << 14) #define GEN6_GT_MODE 0x20d0 #define GEN6_GT_MODE_HI (1 << 9) diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c index ef68037..af7adb0 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -503,13 +503,20 @@ static int init_render_ring(struct intel_ring_buffer *ring) struct drm_i915_private *dev_priv = dev->dev_private; int ret = init_ring_common(ring); - if (INTEL_INFO(dev)->gen > 3) { + if (INTEL_INFO(dev)->gen > 3) I915_WRITE(MI_MODE, _MASKED_BIT_ENABLE(VS_TIMER_DISPATCH)); - if (IS_GEN7(dev)) - I915_WRITE(GFX_MODE_GEN7, - _MASKED_BIT_DISABLE(GFX_TLB_INVALIDATE_ALWAYS) | - _MASKED_BIT_ENABLE(GFX_REPLAY_MODE)); - } + + /* We need to disable the AsyncFlip performance optimisations in order + * to use MI_WAIT_FOR_EVENT within the CS. It should already be + * programmed to '1' on all products. + */ + if (INTEL_INFO(dev)->gen >= 6) + I915_WRITE(MI_MODE, _MASKED_BIT_ENABLE(ASYNC_FLIP_PERF_DISABLE)); + + if (IS_GEN7(dev)) + I915_WRITE(GFX_MODE_GEN7, + _MASKED_BIT_DISABLE(GFX_TLB_INVALIDATE_ALWAYS) | + _MASKED_BIT_ENABLE(GFX_REPLAY_MODE)); if (INTEL_INFO(dev)->gen >= 5) { ret = init_pipe_control(ring); -- 1.7.10.4 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx
