On Tue, Apr 22, 2014 at 01:06:45PM +0000, Mateo Lozano, Oscar wrote: > > 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) Yeah, this is a bit too much magic. Also it looks like it doesn't really help the bug report with his gm45, so I think I'll punt on this one for now. All other patches merged with the 2 small suggestions from Oscar applied while merging. Thanks for patches&review. -Daniel -- 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
