[Intel-gfx] [PATCH] drm/i915: Enforce that CS packets are qword aligned

[Chris Wilson]

Quoting Tvrtko Ursulin (2017-07-24 09:06:28)
> 
> 
> On 21/07/2017 17:11, Chris Wilson wrote:
> > We require the caller to ensure that the packets they wish to emit into
> > the CS ring are qword aligned (i.e. have an even number of dwords).
> > Double check this.
> > 
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
> > Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> > ---
> >   drivers/gpu/drm/i915/intel_ringbuffer.c | 3 +++
> >   1 file changed, 3 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> > index aa59290cb8bf..0b06f66507a0 100644
> > --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> > @@ -1397,6 +1397,9 @@ u32 *intel_ring_begin(struct drm_i915_gem_request *req,
> >       unsigned int total_bytes;
> >       u32 *cs;
> >   
> > +     /* Packets must be qword aligned. */
> > +     GEM_BUG_ON(num_dwords & 1);
> > +
> >       total_bytes = bytes + req->reserved_space;
> >       GEM_BUG_ON(total_bytes > ring->effective_size);
> >   
> > 
> 
> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

And pushed! Still looking for takers to review a regression fix or
two... :-p
-Chris