[Mesa-dev] [PATCH] i965: set size of txf_mcs payload vgrf properly

[Kenneth Graunke]

On 01/03/2014 06:44 PM, Chris Forbes wrote:
> Previously we left the size of this vgrf as 1, which caused register
> allocation to be subtly broken. If we were lucky we would explode in
> the post-alloc instruction scheduler; if we were unlucky we'd just stomp
> on someone else and get broken rendering.
> 
> Fixes crash when running `tesseract` with the following settings:
> 
>    msaa 4
>    glineardepth 0
> 
> Also fixes the piglit test:
> 
>   arb_sample_shading-builtin-gl-sample-id
> 
> Signed-off-by: Chris Forbes <chrisf at ijw.co.nz>
> Cc: Anuj Phogat <anuj.phogat at gmail.com>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=72859
> ---
>  src/mesa/drivers/dri/i965/brw_fs_visitor.cpp | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
> index 8e516a5..53cd0a1 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
> @@ -1549,6 +1549,7 @@ fs_visitor::emit_mcs_fetch(ir_texture *ir, fs_reg coordinate, int sampler)
>     }
>  
>     fs_inst *inst = emit(SHADER_OPCODE_TXF_MCS, dest, payload);
> +   virtual_grf_sizes[payload.reg] = next.reg_offset;
>     inst->base_mrf = -1;
>     inst->mlen = next.reg_offset * reg_width;
>     inst->header_present = false;
> 

Whoops.  Easy to do, seeing as this wasn't necessary with the MRF-based
model...

Cc: "10.0" <mesa-stable at lists.freedesktop.org>
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>