From ad1d219974a3d13412268525309c5892f6779ae9 Mon Sep 17 00:00:00 2001 From: Ben Widawsky Date: Sat, 28 Dec 2013 13:31:49 -0800 Subject: [PATCH] drm/i915: set ctx->initialized only after RCS 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 marked as initialized, but isn't 2. 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 Signed-off-by: Ben Widawsky Reviewed-by: Chris Wilson [danvet: Simplify the failure scenario in the commit message according to Chris' review a bit.] Signed-off-by: Daniel Vetter --- 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 c5975f6d12fb..112f8657db21 100644 --- a/drivers/gpu/drm/i915/i915_gem_context.c +++ b/drivers/gpu/drm/i915/i915_gem_context.c @@ -692,10 +692,11 @@ 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; -- 2.20.1