[Mesa-dev] [PATCH] radeonsi: If pixel shader compilation fails, use a dummy shader.

[Michel Dänzer]

From: Michel Dänzer <michel.daenzer at amd.com>

Otherwise we're likely to hang the GPU.

Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
---
 src/gallium/drivers/radeonsi/radeonsi_pipe.c   |   10 ++++++++++
 src/gallium/drivers/radeonsi/radeonsi_pipe.h   |    4 ++++
 src/gallium/drivers/radeonsi/radeonsi_shader.c |    5 ++++-
 src/gallium/drivers/radeonsi/si_state_draw.c   |    7 +++++++
 4 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/src/gallium/drivers/radeonsi/radeonsi_pipe.c b/src/gallium/drivers/radeonsi/radeonsi_pipe.c
index 3c5eaf7..9ee96a0 100644
--- a/src/gallium/drivers/radeonsi/radeonsi_pipe.c
+++ b/src/gallium/drivers/radeonsi/radeonsi_pipe.c
@@ -37,6 +37,7 @@
 #include "util/u_pack_color.h"
 #include "util/u_memory.h"
 #include "util/u_inlines.h"
+#include "util/u_simple_shaders.h"
 #include "util/u_upload_mgr.h"
 #include "vl/vl_decoder.h"
 #include "vl/vl_video_buffer.h"
@@ -171,6 +172,9 @@ static void r600_destroy_context(struct pipe_context *context)
 {
 	struct r600_context *rctx = (struct r600_context *)context;
 
+	if (rctx->dummy_pixel_shader) {
+		rctx->context.delete_fs_state(&rctx->context, rctx->dummy_pixel_shader);
+	}
 	rctx->context.delete_depth_stencil_alpha_state(&rctx->context, rctx->custom_dsa_flush);
 	util_unreference_framebuffer_state(&rctx->framebuffer);
 
@@ -251,6 +255,12 @@ static struct pipe_context *r600_create_context(struct pipe_screen *screen, void
 
 	r600_get_backend_mask(rctx); /* this emits commands and must be last */
 
+	rctx->dummy_pixel_shader =
+		util_make_fragment_cloneinput_shader(&rctx->context, 0,
+						     TGSI_SEMANTIC_GENERIC,
+						     TGSI_INTERPOLATE_CONSTANT);
+	rctx->context.bind_fs_state(&rctx->context, rctx->dummy_pixel_shader);
+
 	return &rctx->context;
 }
 
diff --git a/src/gallium/drivers/radeonsi/radeonsi_pipe.h b/src/gallium/drivers/radeonsi/radeonsi_pipe.h
index bde468c..3bba6d1 100644
--- a/src/gallium/drivers/radeonsi/radeonsi_pipe.h
+++ b/src/gallium/drivers/radeonsi/radeonsi_pipe.h
@@ -206,6 +206,10 @@ struct r600_context {
 	struct pipe_vertex_buffer vertex_buffer[PIPE_MAX_ATTRIBS];
 	unsigned		nr_vertex_buffers;
 
+	/* With rasterizer discard, there doesn't have to be a pixel shader.
+	 * In that case, we bind this one: */
+	struct si_pipe_shader	*dummy_pixel_shader;
+
 	/* SI state handling */
 	union si_state	queued;
 	union si_state	emitted;
diff --git a/src/gallium/drivers/radeonsi/radeonsi_shader.c b/src/gallium/drivers/radeonsi/radeonsi_shader.c
index 5313e5e..a050617 100644
--- a/src/gallium/drivers/radeonsi/radeonsi_shader.c
+++ b/src/gallium/drivers/radeonsi/radeonsi_shader.c
@@ -627,7 +627,10 @@ int si_pipe_shader_create(
 		tgsi_dump(shader->tokens, 0);
 	}
 
-	lp_build_tgsi_llvm(bld_base, shader->tokens);
+	if (!lp_build_tgsi_llvm(bld_base, shader->tokens)) {
+		fprintf(stderr, "Failed to translate shader from TGSI to LLVM\n");
+		return -EINVAL;
+	}
 
 	radeon_llvm_finalize_module(&si_shader_ctx.radeon_bld);
 
diff --git a/src/gallium/drivers/radeonsi/si_state_draw.c b/src/gallium/drivers/radeonsi/si_state_draw.c
index 0d9f009..7af1944 100644
--- a/src/gallium/drivers/radeonsi/si_state_draw.c
+++ b/src/gallium/drivers/radeonsi/si_state_draw.c
@@ -373,6 +373,13 @@ static void si_update_derived_state(struct r600_context *rctx)
 	if (!rctx->ps_shader->bo) {
 		si_pipe_shader_ps(ctx, rctx->ps_shader);
 	}
+	if (!rctx->ps_shader->bo) {
+		if (!rctx->dummy_pixel_shader->bo)
+			si_pipe_shader_ps(ctx, rctx->dummy_pixel_shader);
+
+		if (rctx->dummy_pixel_shader->pm4)
+			si_pm4_bind_state(rctx, vs, rctx->dummy_pixel_shader->pm4);
+	}
 
 	if (rctx->shader_dirty) {
 		si_update_spi_map(rctx);
-- 
1.7.10.4