[PATCH i-g-t] lib/rendercopy: Fix Xe2 pixel shader

[Juha-Pekka Heikkila]

I was all evening reading the spec and comparing code but I didn't also 
find place which would point this change in spec. I suspect it relate to 
that simd mode change when compare to those older shaders. I agree with 
the change as the code works but I'll still try to figure out where this 
is coming from.

Reviewed-by: Juha-Pekka Heikkila <juhapekka.heikkila at gmail.com>

On 26.2.2024 13.45, Zbigniew Kempczyński wrote:
> On Xe2 start and coefficient for barycentric positions are passed
> in different location of grf register (r6). I wasn't able to find
> this information explicitly in the documentation so I've dumped
> all registers involved in the operation and deduce r6 values
> meaning. This means I may be wrong but tests which are previously
> failing on render-copy now are working fine.
> 
> Signed-off-by: Zbigniew Kempczyński <zbigniew.kempczynski at intel.com>
> Cc: Juha-Pekka Heikkila <juhapekka.heikkila at gmail.com>
> Cc: Swati Sharma <swati2.sharma at intel.com>
> ---
>   lib/i915/shaders/ps/gen20_render_copy.asm | 4 ++--
>   lib/rendercopy_gen9.c                     | 4 ++--
>   2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/lib/i915/shaders/ps/gen20_render_copy.asm b/lib/i915/shaders/ps/gen20_render_copy.asm
> index 330417966d..48057f441e 100644
> --- a/lib/i915/shaders/ps/gen20_render_copy.asm
> +++ b/lib/i915/shaders/ps/gen20_render_copy.asm
> @@ -1,7 +1,7 @@
>   L0:
> -(W)     mad (16|M0)              acc0.0<1>:f   r6.3<0;0>:f      r1.0<1;1>:f       r6.0<0>:f
> +(W)     mad (16|M0)              acc0.0<1>:f   r6.0<0;0>:f      r1.0<1;1>:f       r6.6<0>:f
>   (W)     mad (16|M0)              r113.0<1>:f   acc0.0<1;1>:f    r1.0<1;1>:f       r6.1<0>:f
> -(W)     mad (16|M0)              acc0.0<1>:f   r6.7<0;0>:f      r1.0<1;1>:f       r6.4<0>:f
> +(W)     mad (16|M0)              acc0.0<1>:f   r6.3<0;0>:f      r1.0<1;1>:f       r6.4<0>:f
>   (W)     mad (16|M0)              r114.0<1>:f   acc0.0<1;1>:f    r2.0<1;1>:f       r6.5<0>:f
>   (W)     send.smpl (16|M0)        r12      r113  null:0  0x0            0x04420001           {F at 1,$0} // wr:2+0, rd:4; simd16 sample:u+v+r+ai+mlod using sampler index 0
>   (W)     send.rc (16|M0)          null     r12   null:0  0x0            0x08031400           {EOT,$0} // wr:4+0, rd:0; full-precision render target write SIMD16; last render target to surface 0
> diff --git a/lib/rendercopy_gen9.c b/lib/rendercopy_gen9.c
> index a4220d78da..dd5f1dd448 100644
> --- a/lib/rendercopy_gen9.c
> +++ b/lib/rendercopy_gen9.c
> @@ -138,9 +138,9 @@ static const uint32_t gen12p71_render_copy[][4] = {
>   };
>   
>   static const uint32_t xe2_render_copy[][4] = {
> -	{ 0x8010005b, 0x200002a0, 0x020a0634, 0x06040105 },
> +	{ 0x8010005b, 0x200002a0, 0x020a0604, 0x06640105 },
>   	{ 0x8010005b, 0x710402a8, 0x020a2001, 0x06140105 },
> -	{ 0x8010005b, 0x200002a0, 0x020a0674, 0x06440105 },
> +	{ 0x8010005b, 0x200002a0, 0x020a0634, 0x06440105 },
>   	{ 0x8010005b, 0x720402a8, 0x020a2001, 0x06540205 },
>   	{ 0x80122031, 0x0c240000, 0x20027114, 0x00800000 },
>   	{ 0x8010c031, 0x00000004, 0x58000c24, 0x00c40000 },