[Mesa-dev] [PATCH 09/12] i965/fs/skl+: Fix calculating gl_SampleID for 16x MSAA

[Neil Roberts]

Anuj Phogat <anuj.phogat at gmail.com> writes:

> As per docs we're supposed to get the per slot SampleID written to
> 15:0 bits in R1.0. I used SSPI to compute the SampleID because I never
> got anything useful in these bits on IVB. Things might have changed on
> later platforms. So, I think it's worth trying to do what docs say.
> I'll send out a patch to add above reasoning as a comment in this
> code.

Oh, that's interesting. The layout of the bits is awkward so I wonder if
it would be quite fiddly to extract and might end up with more code than
using the SSPI. It also seems to be missing the IDs for SIMD16.

Regards,
- Neil