Re: [PATCH] drm/i915: Apply post-sync write for pipe control invalidates

[Daniel Vetter <daniel@ffwll.ch>]

jk Sat, Aug 11, 2012 at 12:20:19PM -0700, Ben Widawsky wrote:
> On Fri, 10 Aug 2012 10:18:10 +0100
> Chris Wilson <chris@chris-wilson.co.uk> wrote:
> 
> > When invalidating the TLBs it is documentated as requiring a post-sync
> > write. Failure to do so seems to result in a GPU hang.
> > 
> > Exposure to this hang on IVB seems to be a result of removing the
> > extra stalls required for SNB pipecontrol workarounds:
> > 
> > commit 6c6cf5aa9c583478b19e23149feaa92d01fb8c2d
> > Author: Chris Wilson <chris@chris-wilson.co.uk>
> > Date:   Fri Jul 20 18:02:28 2012 +0100
> > 
> >     drm/i915: Only apply the SNB pipe control w/a to gen6
> > 
> > Reported-by: yex.tian@intel.com
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=53322
> > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> 
> This is the moral equivalent of my patch to make the simulator happy
> on IVB. Daniel, I'll settle for either patch.
> Therefore,
> Acked-by: Ben Widawsky <ben@bwidawsk.net>

Patch merged to -fixes, with some manual frobbery to ensure we get a load
conflict instead of a silent one.
-Daniel

> 
> > ---
> >  drivers/gpu/drm/i915/intel_ringbuffer.c |   35
> > ++++++++++++++++++------------- 1 file changed, 21 insertions(+), 14
> > deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c
> > b/drivers/gpu/drm/i915/intel_ringbuffer.c index 13318a0..7608bc2
> > 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> > @@ -213,20 +213,27 @@ gen6_render_ring_flush(struct intel_ring_buffer
> > *ring,
> >  	 * number of bits based on the write domains has little
> > performance
> >  	 * impact.
> >  	 */
> > -	flags |= PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH;
> > -	flags |= PIPE_CONTROL_TLB_INVALIDATE;
> > -	flags |= PIPE_CONTROL_INSTRUCTION_CACHE_INVALIDATE;
> > -	flags |= PIPE_CONTROL_TEXTURE_CACHE_INVALIDATE;
> > -	flags |= PIPE_CONTROL_DEPTH_CACHE_FLUSH;
> > -	flags |= PIPE_CONTROL_VF_CACHE_INVALIDATE;
> > -	flags |= PIPE_CONTROL_CONST_CACHE_INVALIDATE;
> > -	flags |= PIPE_CONTROL_STATE_CACHE_INVALIDATE;
> > -	/*
> > -	 * Ensure that any following seqno writes only happen when
> > the render
> > -	 * cache is indeed flushed (but only if the caller actually
> > wants that).
> > -	 */
> > -	if (flush_domains)
> > +	if (flush_domains) {
> > +		flags |= PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH;
> > +		flags |= PIPE_CONTROL_DEPTH_CACHE_FLUSH;
> > +		/*
> > +		 * Ensure that any following seqno writes only happen
> > +		 * when the render cache is indeed flushed.
> > +		 */
> >  		flags |= PIPE_CONTROL_CS_STALL;
> > +	}
> > +	if (invalidate_domains) {
> > +		flags |= PIPE_CONTROL_TLB_INVALIDATE;
> > +		flags |= PIPE_CONTROL_INSTRUCTION_CACHE_INVALIDATE;
> > +		flags |= PIPE_CONTROL_TEXTURE_CACHE_INVALIDATE;
> > +		flags |= PIPE_CONTROL_VF_CACHE_INVALIDATE;
> > +		flags |= PIPE_CONTROL_CONST_CACHE_INVALIDATE;
> > +		flags |= PIPE_CONTROL_STATE_CACHE_INVALIDATE;
> > +		/*
> > +		 * TLB invalidate requires a post-sync write.
> > +		 */
> > +		flags |= PIPE_CONTROL_QW_WRITE;
> > +	}
> >  
> >  	ret = intel_ring_begin(ring, 4);
> >  	if (ret)
> > @@ -234,7 +241,7 @@ gen6_render_ring_flush(struct intel_ring_buffer
> > *ring, 
> >  	intel_ring_emit(ring, GFX_OP_PIPE_CONTROL(4));
> >  	intel_ring_emit(ring, flags);
> > -	intel_ring_emit(ring, 0);
> > +	intel_ring_emit(ring, (u32)ring->status_page.gfx_addr+2048);
> >  	intel_ring_emit(ring, 0);
> >  	intel_ring_advance(ring);
> >  
> 
> 
> 
> -- 
> Ben Widawsky, Intel Open Source Technology Center
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-- 
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48