[Mesa-dev] [PATCH 4/4] radeonsi: add a workaround for inexact SNORM8 blitting again

[Nicolai Hähnle]

On 17.06.2017 15:44, Marek Olšák wrote:
> From: Marek Olšák <marek.olsak at amd.com>
> 
> GFX9 is affected.
> ---
>   src/gallium/drivers/radeonsi/si_blit.c | 36 ++++++++++++++++++++++++++++++++++
>   1 file changed, 36 insertions(+)
> 
> diff --git a/src/gallium/drivers/radeonsi/si_blit.c b/src/gallium/drivers/radeonsi/si_blit.c
> index 1159594..b78fddf 100644
> --- a/src/gallium/drivers/radeonsi/si_blit.c
> +++ b/src/gallium/drivers/radeonsi/si_blit.c
> @@ -1133,20 +1133,56 @@ void si_resource_copy_region(struct pipe_context *ctx,
>   				src_templ.format = PIPE_FORMAT_R32G32B32A32_UINT;
>   				break;
>   			default:
>   				fprintf(stderr, "Unhandled format %s with blocksize %u\n",
>   					util_format_short_name(src->format), blocksize);
>   				assert(0);
>   			}
>   		}
>   	}
>   
> +	/* SNORM8 blitting has precision issues on some chips. Use the SINT
> +	 * equivalent instead, which doesn't force DCC decompression.
> +	 * Note that some chips avoid this issue by using SDMA.
> +	 */
> +	if (util_format_is_snorm8(dst_templ.format)) {
> +		switch (dst_templ.format) {
> +		case PIPE_FORMAT_R8_SNORM:
> +			dst_templ.format = src_templ.format = PIPE_FORMAT_R8_SINT;
> +			break;
> +		case PIPE_FORMAT_R8G8_SNORM:
> +			dst_templ.format = src_templ.format = PIPE_FORMAT_R8G8_SINT;
> +			break;
> +		case PIPE_FORMAT_R8G8B8X8_SNORM:
> +			dst_templ.format = src_templ.format = PIPE_FORMAT_R8G8B8X8_SINT;
> +			break;
> +		case PIPE_FORMAT_R8G8B8A8_SNORM:
> +		case PIPE_FORMAT_A8B8G8R8_SNORM: /* also swizzle */
> +		case PIPE_FORMAT_X8B8G8R8_SNORM: /* also swizzle */
> +			dst_templ.format = src_templ.format = PIPE_FORMAT_R8G8B8A8_SINT;

Why does R8G8B8X8 need a separate case but not X8B8G8R8?

Do we have a test for this?

Cheers,
Nicolai


> +			break;
> +		case PIPE_FORMAT_A8_SNORM:
> +			dst_templ.format = src_templ.format = PIPE_FORMAT_A8_SINT;
> +			break;
> +		case PIPE_FORMAT_L8_SNORM:
> +			dst_templ.format = src_templ.format = PIPE_FORMAT_L8_SINT;
> +			break;
> +		case PIPE_FORMAT_L8A8_SNORM:
> +			dst_templ.format = src_templ.format = PIPE_FORMAT_L8A8_SINT;
> +			break;
> +		case PIPE_FORMAT_I8_SNORM:
> +			dst_templ.format = src_templ.format = PIPE_FORMAT_I8_SINT;
> +			break;
> +		default:; /* fall through */
> +		}
> +	}
> +
>   	vi_disable_dcc_if_incompatible_format(&sctx->b, dst, dst_level,
>   					      dst_templ.format);
>   	vi_disable_dcc_if_incompatible_format(&sctx->b, src, src_level,
>   					      src_templ.format);
>   
>   	/* Initialize the surface. */
>   	dst_view = r600_create_surface_custom(ctx, dst, &dst_templ,
>   					      dst_width0, dst_height0,
>   					      dst_width, dst_height);
>   
> 


-- 
Lerne, wie die Welt wirklich ist,
Aber vergiss niemals, wie sie sein sollte.