radeonsi: clarify a hw bug in shader exports

Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>

diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index 09d7849a373e28cf003f9b789f89196d320605b2..169449054add6e7aa4f6bedcc5c1229212e89d61 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -59,6 +59,7 @@ struct si_shader_context
        struct tgsi_parse_context parse;
        struct tgsi_token * tokens;
        struct si_shader *shader;
+       struct si_screen *screen;
        unsigned type; /* TGSI_PROCESSOR_* specifies the type of shader. */
        int param_streamout_config;
        int param_streamout_write_index;
@@ -1400,10 +1401,7 @@ static void si_llvm_emit_fs_epilogue(struct lp_build_tgsi_context * bld_base)
                if (stencil_index >= 0) {
                        out_ptr = si_shader_ctx->radeon_bld.soa.outputs[stencil_index][1];
                        args[6] = LLVMBuildLoad(base->gallivm->builder, out_ptr, "");
-                       /* Only setting the stencil component bit (0x2) here
-                        * breaks some stencil piglit tests
-                        */
-                       mask |= 0x3;
+                       mask |= 0x2;
                        si_shader_ctx->shader->db_shader_control |=
                                S_02880C_STENCIL_TEST_VAL_EXPORT_ENABLE(1);
                }
@@ -1411,10 +1409,16 @@ static void si_llvm_emit_fs_epilogue(struct lp_build_tgsi_context * bld_base)
                if (samplemask_index >= 0) {
                        out_ptr = si_shader_ctx->radeon_bld.soa.outputs[samplemask_index][0];
                        args[7] = LLVMBuildLoad(base->gallivm->builder, out_ptr, "");
-                       mask |= 0xf; /* Set all components. */
+                       mask |= 0x4;
                        si_shader_ctx->shader->db_shader_control |= S_02880C_MASK_EXPORT_ENABLE(1);
                }
 
+               /* SI (except OLAND) has a bug that it only looks
+                * at the X writemask component. */
+               if (si_shader_ctx->screen->b.chip_class == SI &&
+                   si_shader_ctx->screen->b.family != CHIP_OLAND)
+                       mask |= 0x1;
+
                if (samplemask_index >= 0)
                        si_shader_ctx->shader->spi_shader_z_format = V_028710_SPI_SHADER_32_ABGR;
                else if (stencil_index >= 0)
@@ -2740,6 +2744,7 @@ int si_shader_create(struct si_screen *sscreen, struct si_shader *shader)
        tgsi_parse_init(&si_shader_ctx.parse, si_shader_ctx.tokens);
        si_shader_ctx.shader = shader;
        si_shader_ctx.type = si_shader_ctx.parse.FullHeader.Processor.Processor;
+       si_shader_ctx.screen = sscreen;
 
        switch (si_shader_ctx.type) {
        case TGSI_PROCESSOR_VERTEX: