On Fri, Jul 13, 2012 at 02:14:08PM +0100, Chris Wilson wrote: > If we drop the breadcrumb request after a batch due to a signal for > example we aim to fix it up at the next opportunity. In this case we > emit a second batchbuffer with no waits upon the first and so no > opportunity to insert the missing request, so we need to emit the > missing flush for coherency. (Note that that invalidating the render > cache is the same as flushing it, so there should have been no > observable corruption.) > > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk> Imo still too meager commit message ;-) As I've said in the previous mail, I'd like some mention of the two commits that made this disaster possible (put the blame on me where it is due). And I think some more in-detail walk-thru of how things blow up would be great. And the Bugzilla link for the QA bugreport. Also, I still don't understand why this patch here isn't enough to fix up the fallout. So if you can enlighten me where/why stuff blows up even with this I'd highly appreciate. Not just because not understanding bugs makes me queasy, but also to have a clear picture of what I'd need to send to Dave it this -next cycle misses 3.6. Meanwhile I'll try to hit this with some i-g-t tests, maybe that gives me better understanding of what's going on. Thanks, Daniel > --- > drivers/gpu/drm/i915/i915_gem_execbuffer.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c > index 50e83e5..c08229f 100644 > --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c > +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c > @@ -885,11 +885,16 @@ i915_gem_execbuffer_move_to_gpu(struct intel_ring_buffer *ring, > return ret; > } > > - /* Unconditionally invalidate gpu caches. */ > - ret = i915_gem_flush_ring(ring, I915_GEM_GPU_DOMAINS, 0); > + /* Unconditionally invalidate gpu caches and ensure that we do flush > + * any residual writes from the previous batch. > + */ > + ret = i915_gem_flush_ring(ring, > + I915_GEM_GPU_DOMAINS, > + ring->gpu_caches_dirty ? I915_GEM_GPU_DOMAINS : 0); > if (ret) > return ret; > > + ring->gpu_caches_dirty = false; > return 0; > } > > -- > 1.7.10.4 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx at lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Daniel Vetter Mail: daniel at ffwll.ch Mobile: +41 (0)79 365 57 48
