Mesa (main): v3d,v3dv: don't disable EZ for passthrough Z writes

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Module: Mesa
Branch: main
Commit: d7b79f3531de5cdee2bb61b54f3549252e7ae97a
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=d7b79f3531de5cdee2bb61b54f3549252e7ae97a

Author: Iago Toral Quiroga <itoral at igalia.com>
Date:   Fri Dec  3 10:29:16 2021 +0100

v3d,v3dv: don't disable EZ for passthrough Z writes

The early-Z test uses Z values produced from FEP, so when
we write Z from a shader we need to disable EZ. However, there
are some instances where want to write the FEP-Z from the shader,
in which case we would not need to disable EZ.

Reviewed-by: Alejandro Piñeiro <apinheiro at igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14037>

---

 src/broadcom/vulkan/v3dvx_cmd_buffer.c | 3 ++-
 src/broadcom/vulkan/v3dvx_pipeline.c   | 1 +
 src/gallium/drivers/v3d/v3dx_draw.c    | 4 +++-
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/broadcom/vulkan/v3dvx_cmd_buffer.c b/src/broadcom/vulkan/v3dvx_cmd_buffer.c
index 4c2b1d4bade..02c24c338be 100644
--- a/src/broadcom/vulkan/v3dvx_cmd_buffer.c
+++ b/src/broadcom/vulkan/v3dvx_cmd_buffer.c
@@ -1429,7 +1429,8 @@ job_update_ez_state(struct v3dv_job *job,
    /* If the FS writes Z, then it may update against the chosen EZ direction */
    struct v3dv_shader_variant *fs_variant =
       pipeline->shared_data->variants[BROADCOM_SHADER_FRAGMENT];
-   if (fs_variant->prog_data.fs->writes_z) {
+   if (fs_variant->prog_data.fs->writes_z &&
+       !fs_variant->prog_data.fs->writes_z_from_fep) {
       job->ez_state = V3D_EZ_DISABLED;
       return;
    }
diff --git a/src/broadcom/vulkan/v3dvx_pipeline.c b/src/broadcom/vulkan/v3dvx_pipeline.c
index 7c6fae22ad1..c17638754d2 100644
--- a/src/broadcom/vulkan/v3dvx_pipeline.c
+++ b/src/broadcom/vulkan/v3dvx_pipeline.c
@@ -388,6 +388,7 @@ pack_shader_state_record(struct v3dv_pipeline *pipeline)
        * shader needs to write the Z value (even just discards).
        */
       shader.fragment_shader_does_z_writes = prog_data_fs->writes_z;
+
       /* Set if the EZ test must be disabled (due to shader side
        * effects and the early_z flag not being present in the
        * shader).
diff --git a/src/gallium/drivers/v3d/v3dx_draw.c b/src/gallium/drivers/v3d/v3dx_draw.c
index ae8537d8347..25ef97f888e 100644
--- a/src/gallium/drivers/v3d/v3dx_draw.c
+++ b/src/gallium/drivers/v3d/v3dx_draw.c
@@ -605,6 +605,7 @@ v3d_emit_gl_shader_state(struct v3d_context *v3d,
                  */
                 shader.fragment_shader_does_z_writes =
                         v3d->prog.fs->prog_data.fs->writes_z;
+
                 /* Set if the EZ test must be disabled (due to shader side
                  * effects and the early_z flag not being present in the
                  * shader).
@@ -879,7 +880,8 @@ v3d_update_job_ez(struct v3d_context *v3d, struct v3d_job *job)
          * the chosen EZ direction (though we could use
          * ARB_conservative_depth's hints to avoid this)
          */
-        if (v3d->prog.fs->prog_data.fs->writes_z) {
+        if (v3d->prog.fs->prog_data.fs->writes_z &&
+            !v3d->prog.fs->prog_data.fs->writes_z_from_fep) {
                 job->ez_state = V3D_EZ_DISABLED;
         }