[Intel-gfx] [PATCH v2] drm/i915: Decouple execbuf uAPI from internal implementation

[Gong, Zhipeng]

> On Fri, Jan 15, 2016 at 03:12:50PM +0000, Tvrtko Ursulin wrote:
> > From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> > +	if (user_ring_id == I915_EXEC_BSD && HAS_BSD2(dev_priv)) {
> > +		unsigned int bsd_idx = args->flags & I915_EXEC_BSD_MASK;
> > +
> > +		if (bsd_idx == I915_EXEC_BSD_DEFAULT) {
> > +			bsd_idx = gen8_dispatch_bsd_ring(dev_priv, file);
> > +		} else if (bsd_idx >= I915_EXEC_BSD_RING1 &&
> > +			   bsd_idx <= I915_EXEC_BSD_RING2) {
> > +			bsd_idx--;

There is one regression here, I915_EXEC_BSD_RING1/2 is left-shifted 13 bits, 
so we should add something like
	bsd_idx >>= 13;
Otherwise the kernel panics.