[Mesa-dev] [PATCH 2/3] i965/fs: do not disable the FS unit in the presence of shader storage

[Iago Toral Quiroga]

We want to make sure that the driver does not disable the FS unit if
the shader code only has SSBO writes (i.e. no color or depth output).

We could go a step further and check if the shader storage is actually
used for writing, but does not seem worth the trouble. Also, we do the
same thing for atomic buffers.

Fixes the following CTS test:
ES31-CTS.shader_storage_buffer_object.advanced-usage-sync-vsfs
---
 src/mesa/drivers/dri/i965/gen7_wm_state.c | 3 ++-
 src/mesa/drivers/dri/i965/gen8_ps_state.c | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/mesa/drivers/dri/i965/gen7_wm_state.c b/src/mesa/drivers/dri/i965/gen7_wm_state.c
index 06d5e65..d292b13 100644
--- a/src/mesa/drivers/dri/i965/gen7_wm_state.c
+++ b/src/mesa/drivers/dri/i965/gen7_wm_state.c
@@ -77,7 +77,8 @@ upload_wm_state(struct brw_context *brw)
       dw1 |= GEN7_WM_KILL_ENABLE;
    }
 
-   if (_mesa_active_fragment_shader_has_atomic_ops(&brw->ctx)) {
+   if (_mesa_active_fragment_shader_has_atomic_ops(&brw->ctx ) ||
+       _mesa_active_fragment_shader_has_shader_storage(&brw->ctx)) {
       dw1 |= GEN7_WM_DISPATCH_ENABLE;
    }
 
diff --git a/src/mesa/drivers/dri/i965/gen8_ps_state.c b/src/mesa/drivers/dri/i965/gen8_ps_state.c
index 945f710..8769269 100644
--- a/src/mesa/drivers/dri/i965/gen8_ps_state.c
+++ b/src/mesa/drivers/dri/i965/gen8_ps_state.c
@@ -91,6 +91,7 @@ gen8_upload_ps_extra(struct brw_context *brw,
     * BRW_NEW_FS_PROG_DATA | BRW_NEW_FRAGMENT_PROGRAM | _NEW_BUFFERS | _NEW_COLOR
     */
    if ((_mesa_active_fragment_shader_has_atomic_ops(&brw->ctx) ||
+        _mesa_active_fragment_shader_has_shader_storage(&brw->ctx) ||
         prog_data->base.nr_image_params) &&
        !brw_color_buffer_write_enabled(brw))
       dw1 |= GEN8_PSX_SHADER_HAS_UAV;
-- 
1.9.1