[Mesa-dev] [PATCH v2 05/20] i965: Use <0, 2, 1> region for scalar DF sources on IVB/BYT.

[Matt Turner]

On Tue, Jan 17, 2017 at 1:33 PM, Francisco Jerez <currojerez at riseup.net> wrote:
> Samuel Iglesias Gonsálvez <siglesias at igalia.com> writes:
>
>> From: Matt Turner <mattst88 at gmail.com>
>>
>> On HSW+, scalar DF sources can be accessed using the normal <0,1,0>
>> region, but on IVB and BYT DF regions must be programmed in terms of
>> floats. A <0,2,1> region accomplishes this.
>
> Any reason you're doing this here twice instead of during fs_reg to
> brw_reg conversion?

I think the reason I didn't do it that way is that sources of type
FIXED_GRF and VGRF both need the fix up, and those are handled by
different code paths in brw_reg_from_fs_reg() (and FIXED_GRF shares a
codepath with ARF and IMM). Fixing it here also handles the case for
the vec4 backend, if that's ever a problem.

I don't have a preference.