[Mesa-dev] [PATCH] radv: adjust the VGT workaround for prim restart on GFX9

[Samuel Pitoiset]

ping?

After looking into this again today, I can't find any better solutions. 
We should probably push this patch because at least two games are 
affected. My opinion is that correctness is more important than performance.

On 10/11/18 10:42 AM, Samuel Pitoiset wrote:
> WD_SWITCH_ON_EOP seems to be the only workaround that fixes
> the GPU hangs with Yakuza and The Evil Within on Vega. I don't
> like as it might decrease geometry performance as pointed out
> by Marek, but I don't know how to implement a better one.
> 
> Cc: mesa-stable at lists.freedesktop.org
> Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
> ---
>   src/amd/vulkan/radv_pipeline.c | 13 +++++++++++--
>   1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/src/amd/vulkan/radv_pipeline.c b/src/amd/vulkan/radv_pipeline.c
> index 426b417e172..2256b2c58e9 100644
> --- a/src/amd/vulkan/radv_pipeline.c
> +++ b/src/amd/vulkan/radv_pipeline.c
> @@ -3412,14 +3412,23 @@ radv_compute_ia_multi_vgt_param_helpers(struct radv_pipeline *pipeline,
>   	}
>   
>   	/* Workaround for a VGT hang when strip primitive types are used with
> -	 * primitive restart.
> +	 * primitive restart. This fixes GPU hangs with Yakuza and The Evil
> +	 * Within, at least. Not sure if we can implement a better workaround.
>   	 */
>   	if (pipeline->graphics.prim_restart_enable &&
>   	    (prim == V_008958_DI_PT_LINESTRIP ||
>   	     prim == V_008958_DI_PT_TRISTRIP ||
>   	     prim == V_008958_DI_PT_LINESTRIP_ADJ ||
>   	     prim == V_008958_DI_PT_TRISTRIP_ADJ)) {
> -		ia_multi_vgt_param.partial_vs_wave = true;
> +		if (device->physical_device->rad_info.chip_class >= GFX9) {
> +			/* XXX: This might decrease geometry performance by 2x,
> +			 * but this appears to be the only workaround that
> +			 * fixes the GPU hang.
> +			 */
> +			ia_multi_vgt_param.wd_switch_on_eop = true;
> +		} else {
> +			ia_multi_vgt_param.partial_vs_wave = true;
> +		}
>   	}
>   
>   	ia_multi_vgt_param.base =
>