freedreno/a6xx: Demote coherent img access to uncompressed

We cannot use UBWC for coherent access across shader stages.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20612>

src/gallium/drivers/freedreno/a6xx/fd6_image.c

@@ -203,7 +203,26 @@ fd6_set_shader_images(struct pipe_context *pctx, enum pipe_shader_type shader,
       if (!buf->resource)
          continue;
 
-      fd6_validate_format(ctx, fd_resource(buf->resource), buf->format);
+      struct fd_resource *rsc = fd_resource(buf->resource);
+
+      if (buf->shader_access & (PIPE_IMAGE_ACCESS_COHERENT |
+                                PIPE_IMAGE_ACCESS_VOLATILE)) {
+         /* UBWC compression cannot be used with coherent/volatile access
+          * due to the extra caching (CCU) involved:
+          */
+         if (rsc->layout.ubwc) {
+            bool linear = fd6_valid_tiling(rsc, buf->format);
+
+            perf_debug_ctx(ctx,
+                           "%" PRSC_FMT ": demoted to %suncompressed due to coherent/volatile use as %s",
+                           PRSC_ARGS(&rsc->b.b), linear ? "linear+" : "",
+                           util_format_short_name(buf->format));
+
+            fd_resource_uncompress(ctx, rsc, linear);
+         }
+      } else {
+         fd6_validate_format(ctx, rsc, buf->format);
+      }
    }
 }
 

src/gallium/drivers/freedreno/a6xx/fd6_resource.c

@@ -160,6 +160,24 @@ is_r8g8(enum pipe_format format)
          (util_format_get_nr_components(format) == 2);
 }
 
+/**
+ * Can a rsc be accessed tiled with the specified format, or does it need to
+ * be linearized?
+ */
+bool
+fd6_valid_tiling(struct fd_resource *rsc, enum pipe_format format)
+{
+   enum pipe_format orig_format = rsc->b.b.format;
+
+   if (orig_format == format)
+      return true;
+
+   if (rsc->layout.tile_mode && (is_r8g8(orig_format) != is_r8g8(format)))
+      return false;
+
+   return true;
+}
+
 /**
  * Ensure the rsc is in an ok state to be used with the specified format.
  * This handles the case of UBWC buffers used with non-UBWC compatible
@@ -176,7 +194,7 @@ fd6_validate_format(struct fd_context *ctx, struct fd_resource *rsc,
    if (orig_format == format)
       return;
 
-   if (rsc->layout.tile_mode && (is_r8g8(orig_format) != is_r8g8(format))) {
+   if (!fd6_valid_tiling(rsc, format)) {
       perf_debug_ctx(ctx,
                      "%" PRSC_FMT ": demoted to linear+uncompressed due to use as %s",
                      PRSC_ARGS(&rsc->b.b), util_format_short_name(format));

src/gallium/drivers/freedreno/a6xx/fd6_resource.h

@@ -30,6 +30,7 @@
 
 #include "freedreno_resource.h"
 
+bool fd6_valid_tiling(struct fd_resource *rsc, enum pipe_format format);
 void fd6_validate_format(struct fd_context *ctx, struct fd_resource *rsc,
                          enum pipe_format format) assert_dt;
 void fd6_emit_flag_reference(struct fd_ringbuffer *ring,