[6/8] drm/i915: TLB invalidation with MI_FLUSH_DW requires a post-sync op

Commit Message

Jesse Barnes Oct. 26, 2012, 4:42 p.m. UTC

On Fri, 26 Oct 2012 12:13:39 +0100
Chris Wilson <[e-mail]> wrote:

> On Thu, 25 Oct 2012 12:15:46 -0700, Jesse Barnes <[e-mail]> wrote:
> > So store into the scratch space of the HWS to make sure the invalidate
> > occurs.
> > 
> > v2: use GTT address space for store, clean up #defines (Chris)
> > 
> > Signed-off-by: Jesse Barnes <[e-mail]>
> > ---
> > @@ -1460,10 +1467,17 @@ static int blt_ring_flush(struct intel_ring_buffer *ring,
> >  		return ret;
> >  
> >  	cmd = MI_FLUSH_DW;
> > +	/*
> > +	 * Bspec vol 1c.3 - blitter engine command streamer:
> > +	 * "If ENABLED, all TLBs will be invalidated once the flush
> > +	 * operation is complete. This bit is only valid when the
> > +	 * Post-Sync Operation field is a value of 1h or 3h."
> > +	 */
> >  	if (invalidate & I915_GEM_DOMAIN_RENDER)
> > -		cmd |= MI_INVALIDATE_TLB;
> > +		cmd |= MI_INVALIDATE_TLB | MI_FLUSH_DW_STORE_INDEX |
> > +			MI_FLUSH_DW_OP_STOREDW | MI_FLUSH_DW_OP_STOREDW;
> >  	intel_ring_emit(ring, cmd);
> > -	intel_ring_emit(ring, 0);
> > +	intel_ring_emit(ring, I915_GEM_HWS_SCRATCH_INDEX | MI_FLUSH_DW_USE_GTT);
> 
> s/SCRATCH_INDEX/SCRATCH_ADDR/
> -Chris
>

Comments

Chris Wilson Nov. 2, 2012, 12:41 p.m. UTC | #1

On Fri, 26 Oct 2012 09:42:42 -0700, Jesse Barnes <[e-mail]> wrote:
> commit b99c792eddf804150b3341a85c256df50d7ab5c2
> Author: Jesse Barnes <[e-mail]>
> Date:   Wed Sep 19 13:02:39 2012 -0700
> 
>     drm/i915: TLB invalidation with MI_FLUSH_DW requires a post-sync op v3
>     
>     So store into the scratch space of the HWS to make sure the invalidate
>     occurs.
>     
>     v2: use GTT address space for store, clean up #defines (Chris)
>     v3: use correct #define in blt ring flush (Chris)
>     
>     Signed-off-by: Jesse Barnes <[e-mail]>

Reviewed-by: Chris Wilson <[e-mail]>

That looks to be the code I executed, but I can't confirm it fixes any
problems.

References: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1063252

which looks to be a likely victim of a missing TLB flush on the blitter
ring.
-Chris

Patch

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index f29401b..ea97430 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -242,8 +242,12 @@ 
  */
 #define MI_LOAD_REGISTER_IMM(x)	MI_INSTR(0x22, 2*x-1)
 #define MI_FLUSH_DW		MI_INSTR(0x26, 1) /* for GEN6 */
-#define   MI_INVALIDATE_TLB	(1<<18)
-#define   MI_INVALIDATE_BSD	(1<<7)
+#define   MI_FLUSH_DW_STORE_INDEX	(1<<21)
+#define   MI_INVALIDATE_TLB		(1<<18)
+#define   MI_FLUSH_DW_OP_STOREDW	(1<<14)
+#define   MI_INVALIDATE_BSD		(1<<7)
+#define   MI_FLUSH_DW_USE_GTT		(1<<2)
+#define   MI_FLUSH_DW_USE_PPGTT		(0<<2)
 #define MI_BATCH_BUFFER		MI_INSTR(0x30, 1)
 #define   MI_BATCH_NON_SECURE		(1)
 /* for snb/ivb/vlv this also means "batch in ppgtt" when ppgtt is enabled. */
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 785df4f..55abda5 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1395,10 +1395,17 @@  static int gen6_ring_flush(struct intel_ring_buffer *ring,
 		return ret;
 
 	cmd = MI_FLUSH_DW;
+	/*
+	 * Bspec vol 1c.5 - video engine command streamer:
+	 * "If ENABLED, all TLBs will be invalidated once the flush
+	 * operation is complete. This bit is only valid when the
+	 * Post-Sync Operation field is a value of 1h or 3h."
+	 */
 	if (invalidate & I915_GEM_GPU_DOMAINS)
-		cmd |= MI_INVALIDATE_TLB | MI_INVALIDATE_BSD;
+		cmd |= MI_INVALIDATE_TLB | MI_INVALIDATE_BSD |
+			MI_FLUSH_DW_STORE_INDEX | MI_FLUSH_DW_OP_STOREDW;
 	intel_ring_emit(ring, cmd);
-	intel_ring_emit(ring, 0);
+	intel_ring_emit(ring, I915_GEM_HWS_SCRATCH_ADDR | MI_FLUSH_DW_USE_GTT);
 	intel_ring_emit(ring, 0);
 	intel_ring_emit(ring, MI_NOOP);
 	intel_ring_advance(ring);
@@ -1460,10 +1467,17 @@  static int blt_ring_flush(struct intel_ring_buffer *ring,
 		return ret;
 
 	cmd = MI_FLUSH_DW;
+	/*
+	 * Bspec vol 1c.3 - blitter engine command streamer:
+	 * "If ENABLED, all TLBs will be invalidated once the flush
+	 * operation is complete. This bit is only valid when the
+	 * Post-Sync Operation field is a value of 1h or 3h."
+	 */
 	if (invalidate & I915_GEM_DOMAIN_RENDER)
-		cmd |= MI_INVALIDATE_TLB;
+		cmd |= MI_INVALIDATE_TLB | MI_FLUSH_DW_STORE_INDEX |
+			MI_FLUSH_DW_OP_STOREDW | MI_FLUSH_DW_OP_STOREDW;
 	intel_ring_emit(ring, cmd);
-	intel_ring_emit(ring, 0);
+	intel_ring_emit(ring, I915_GEM_HWS_SCRATCH_ADDR | MI_FLUSH_DW_USE_GTT);
 	intel_ring_emit(ring, 0);
 	intel_ring_emit(ring, MI_NOOP);
 	intel_ring_advance(ring);
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 3745d1d..5af65b8 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -183,6 +183,8 @@  intel_read_status_page(struct intel_ring_buffer *ring,
  * The area from dword 0x20 to 0x3ff is available for driver usage.
  */
 #define I915_GEM_HWS_INDEX		0x20
+#define I915_GEM_HWS_SCRATCH_INDEX	0x30
+#define I915_GEM_HWS_SCRATCH_ADDR (I915_GEM_HWS_SCRATCH_INDEX << MI_STORE_DWORD_INDEX_SHIFT)
 
 void intel_cleanup_ring_buffer(struct intel_ring_buffer *ring);