[Mesa-dev] [PATCH 07/17] radeonsi: skip DCC render feedback checking if color writes are disabled

[Timothy Arceri]

This change cause around 20+ piglit crashes on my Polaris.

e.g tests/spec/arb_compute_shader/execution/atomic-counter.shader_test

Thread 1 "shader_runner" received signal SIGSEGV, Segmentation fault.
0x00007ffff1009ccc in si_get_total_colormask (sctx=0x64b140) at 
si_pipe.h:945
945		if (sctx->queued.named.rasterizer->rasterizer_discard)


It also seems to cause hundreds of test failures e.g

./bin/copyteximage CUBE -auto


Unfortunately it doesn't revert cleanly either.

On 04/04/18 11:59, Marek Olšák wrote:
> From: Marek Olšák <marek.olsak at amd.com>
> 
> The previous patch is required for this.
> ---
>   src/gallium/drivers/radeonsi/si_blit.c          |  5 +++++
>   src/gallium/drivers/radeonsi/si_pipe.h          | 17 +++++++++++++++++
>   src/gallium/drivers/radeonsi/si_state_shaders.c |  6 +-----
>   3 files changed, 23 insertions(+), 5 deletions(-)
> 
> diff --git a/src/gallium/drivers/radeonsi/si_blit.c b/src/gallium/drivers/radeonsi/si_blit.c
> index 45770b0d9bf..8dd8bc2a4dd 100644
> --- a/src/gallium/drivers/radeonsi/si_blit.c
> +++ b/src/gallium/drivers/radeonsi/si_blit.c
> @@ -706,20 +706,25 @@ static void si_check_render_feedback_resident_images(struct si_context *sctx)
>   		si_check_render_feedback_texture(sctx, tex,
>   						 view->u.tex.level,
>   						 view->u.tex.level,
>   						 view->u.tex.first_layer,
>   						 view->u.tex.last_layer);
>   	}
>   }
>   
>   static void si_check_render_feedback(struct si_context *sctx)
>   {
> +	/* There is no render feedback if color writes are disabled.
> +	 * (e.g. a pixel shader with image stores)
> +	 */
> +	if (!si_get_total_colormask(sctx))
> +		return;
>   
>   	if (!sctx->need_check_render_feedback)
>   		return;
>   
>   	for (int i = 0; i < SI_NUM_SHADERS; ++i) {
>   		si_check_render_feedback_images(sctx, &sctx->images[i]);
>   		si_check_render_feedback_textures(sctx, &sctx->samplers[i]);
>   	}
>   
>   	si_check_render_feedback_resident_images(sctx);
> diff --git a/src/gallium/drivers/radeonsi/si_pipe.h b/src/gallium/drivers/radeonsi/si_pipe.h
> index e3d45ef6c3b..e65c946d186 100644
> --- a/src/gallium/drivers/radeonsi/si_pipe.h
> +++ b/src/gallium/drivers/radeonsi/si_pipe.h
> @@ -933,11 +933,28 @@ vi_tc_compat_htile_enabled(struct r600_texture *tex, unsigned level)
>   }
>   
>   static inline unsigned si_get_ps_iter_samples(struct si_context *sctx)
>   {
>   	if (sctx->ps_uses_fbfetch)
>   		return sctx->framebuffer.nr_samples;
>   
>   	return sctx->ps_iter_samples;
>   }
>   
> +static inline unsigned si_get_total_colormask(struct si_context *sctx)
> +{
> +	if (sctx->queued.named.rasterizer->rasterizer_discard)
> +		return 0;
> +
> +	struct si_shader_selector *ps = sctx->ps_shader.cso;
> +	unsigned colormask = sctx->framebuffer.colorbuf_enabled_4bit &
> +			     sctx->queued.named.blend->cb_target_mask;
> +
> +	if (!ps->info.properties[TGSI_PROPERTY_FS_COLOR0_WRITES_ALL_CBUFS])
> +		colormask &= ps->colors_written_4bit;
> +	else if (!ps->colors_written_4bit)
> +		colormask = 0; /* color0 writes all cbufs, but it's not written */
> +
> +	return colormask;
> +}
> +
>   #endif
> diff --git a/src/gallium/drivers/radeonsi/si_state_shaders.c b/src/gallium/drivers/radeonsi/si_state_shaders.c
> index d7742eafb04..f2d29e40744 100644
> --- a/src/gallium/drivers/radeonsi/si_state_shaders.c
> +++ b/src/gallium/drivers/radeonsi/si_state_shaders.c
> @@ -1208,25 +1208,21 @@ static void si_shader_selector_key_hw_vs(struct si_context *sctx,
>   	bool ps_disabled = true;
>   	if (ps) {
>   		const struct si_state_blend *blend = sctx->queued.named.blend;
>   		bool alpha_to_coverage = blend && blend->alpha_to_coverage;
>   		bool ps_modifies_zs = ps->info.uses_kill ||
>   				      ps->info.writes_z ||
>   				      ps->info.writes_stencil ||
>   				      ps->info.writes_samplemask ||
>   				      alpha_to_coverage ||
>   				      si_get_alpha_test_func(sctx) != PIPE_FUNC_ALWAYS;
> -
> -		unsigned ps_colormask = sctx->framebuffer.colorbuf_enabled_4bit &
> -					sctx->queued.named.blend->cb_target_mask;
> -		if (!ps->info.properties[TGSI_PROPERTY_FS_COLOR0_WRITES_ALL_CBUFS])
> -			ps_colormask &= ps->colors_written_4bit;
> +		unsigned ps_colormask = si_get_total_colormask(sctx);
>   
>   		ps_disabled = sctx->queued.named.rasterizer->rasterizer_discard ||
>   			      (!ps_colormask &&
>   			       !ps_modifies_zs &&
>   			       !ps->info.writes_memory);
>   	}
>   
>   	/* Find out which VS outputs aren't used by the PS. */
>   	uint64_t outputs_written = vs->outputs_written;
>   	uint64_t inputs_read = 0;
>