[Mesa-dev] [PATCH] radv: fix issue with multisample positions and interp_var_at_sample.

[Samuel Pitoiset]

I think this needs to be backported to mesa-stable.

Thanks for fixing this, it makes sense.

Reviewed-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>

On 12/21/2017 05:05 AM, Dave Airlie wrote:
> From: Dave Airlie <airlied at redhat.com>
> 
> This fixes vmfaults seen on vega with:
> dEQP-VK.pipeline.multisample_interpolation.sample_interpolate_at_single_sample_.128_128_1.samples_1
> 
> These were caused by the don't allocate cmask but it was just accidental.
> 
> The actual problem was the shader was trying to get the sample positions from
> a buffer, but the buffer was never getting configured to contain them, as the
> previous shader never needed them.
> 
> Signed-off-by: Dave Airlie <airlied at redhat.com>
> ---
>   src/amd/vulkan/radv_cmd_buffer.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/src/amd/vulkan/radv_cmd_buffer.c b/src/amd/vulkan/radv_cmd_buffer.c
> index a366facd63..6a89d4e568 100644
> --- a/src/amd/vulkan/radv_cmd_buffer.c
> +++ b/src/amd/vulkan/radv_cmd_buffer.c
> @@ -593,7 +593,8 @@ radv_update_multisample_state(struct radv_cmd_buffer *cmd_buffer,
>   	radeon_set_context_reg(cmd_buffer->cs, R_028804_DB_EQAA, ms->db_eqaa);
>   	radeon_set_context_reg(cmd_buffer->cs, R_028A4C_PA_SC_MODE_CNTL_1, ms->pa_sc_mode_cntl_1);
>   
> -	if (old_pipeline && num_samples == old_pipeline->graphics.ms.num_samples)
> +	if (old_pipeline && num_samples == old_pipeline->graphics.ms.num_samples &&
> +	    old_pipeline->shaders[MESA_SHADER_FRAGMENT]->info.info.ps.needs_sample_positions == pipeline->shaders[MESA_SHADER_FRAGMENT]->info.info.ps.needs_sample_positions)
>   		return;
>   
>   	radeon_set_context_reg_seq(cmd_buffer->cs, R_028BDC_PA_SC_LINE_CNTL, 2);
>