On Sat, Dec 28, 2013 at 01:31:49PM -0800, Ben Widawsky wrote: > The initialized flag is used to specify a context has been initialized > and it's context is safe to load, ie. the 3d state is setup properly. > With full PPGTT, we emit the address space loads during context switch > and this currently marks a context as initialized. With full PPGTT > patches, if a client first emits a batch to !RCS, then later, RCS, the > code will mistake the context as initialized and try to reload an > uninitialized context. > > 1. context 1 blit // context initialized > 2. context 2 <X operation> // saves context 1 random state > 3. context 1 render // loads random state from step 2 > > It is really easy to hit this with a planned upcoming patch which makes > default context reuse possible. > > NOTE: This should only effect full PPGTT branches, ie. current > drm-intel-nightly. > > Thanks to Chris for helping me track this down. > > Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Signed-off-by: Ben Widawsky <ben@xxxxxxxxxxxx> Do we have a testcase for this or a bug report? -Daniel > --- > drivers/gpu/drm/i915/i915_gem_context.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c > index ebe0f67..28b9f30 100644 > --- a/drivers/gpu/drm/i915/i915_gem_context.c > +++ b/drivers/gpu/drm/i915/i915_gem_context.c > @@ -686,10 +686,11 @@ static int do_switch(struct intel_ring_buffer *ring, > i915_gem_context_unreference(from); > } > > + to->is_initialized = true; > + > done: > i915_gem_context_reference(to); > ring->last_context = to; > - to->is_initialized = true; > to->last_ring = ring; > > return 0; > -- > 1.8.5.2 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
