> Subject: [PATCH 6/6] drm/i915: Kick start the rings > > On g4x, we have an issue where the register write to setup the rings do not > always take. However, it appears that the current check also passes only by > chance, a second reading of the register returns a different broekn value - but > the GPU appears to function. Based on that observation, lets try feeding a nop > into the ring and seeing if it advances as part of our startup sanity checks. > > References: https://bugs.freedesktop.org/show_bug.cgi?id=76554 > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > --- > drivers/gpu/drm/i915/intel_ringbuffer.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c > b/drivers/gpu/drm/i915/intel_ringbuffer.c > index a8c73a0d935d..bc52645fa8d5 100644 > --- a/drivers/gpu/drm/i915/intel_ringbuffer.c > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c > @@ -514,10 +514,14 @@ static int init_ring_common(struct intel_ring_buffer > *ring) > ((ring->size - PAGE_SIZE) & RING_NR_PAGES) > | RING_VALID); > > + iowrite32(MI_NOOP, ring->virtual_start + 0); > + iowrite32(MI_NOOP, ring->virtual_start + 4); > + ring->write_tail(ring, 8); Maybe add a comment in the code about why we are doing this? (otherwise, it looks a bit magical) > /* If the head is still not zero, the ring is dead */ > if (wait_for((I915_READ_CTL(ring) & RING_VALID) != 0 && > I915_READ_START(ring) == i915_gem_obj_ggtt_offset(obj) > && > - (I915_READ_HEAD(ring) & HEAD_ADDR) == 0, 50)) { > + (I915_READ_HEAD(ring) & HEAD_ADDR) == 8, 50)) { > DRM_ERROR("%s initialization failed " > "ctl %08x (valid? %d) head %08x tail %08x start %08x > [expected %08lx]\n", > ring->name, > -- > 1.9.1 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > http://lists.freedesktop.org/mailman/listinfo/intel-gfx _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
