radeonsi: add a debug option that disables DCC for all exported buffers

requested internally

Reviewed-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14283>

src/gallium/drivers/radeonsi/si_pipe.c

@@ -105,6 +105,7 @@ static const struct debug_named_value radeonsi_debug_options[] = {
    {"notiling", DBG(NO_TILING), "Disable tiling"},
    {"nodisplaytiling", DBG(NO_DISPLAY_TILING), "Disable display tiling"},
    {"nodisplaydcc", DBG(NO_DISPLAY_DCC), "Disable display DCC"},
+   {"noexporteddcc", DBG(NO_EXPORTED_DCC), "Disable DCC for all exported buffers (via DMABUF, etc.)"},
    {"nodcc", DBG(NO_DCC), "Disable DCC."},
    {"nodccclear", DBG(NO_DCC_CLEAR), "Disable DCC fast clear."},
    {"nodccstore", DBG(NO_DCC_STORE), "Disable DCC stores"},

src/gallium/drivers/radeonsi/si_pipe.h

@@ -237,6 +237,7 @@ enum
    DBG_NO_TILING,
    DBG_NO_DISPLAY_TILING,
    DBG_NO_DISPLAY_DCC,
+   DBG_NO_EXPORTED_DCC,
    DBG_NO_DCC,
    DBG_NO_DCC_CLEAR,
    DBG_NO_DCC_STORE,

src/gallium/drivers/radeonsi/si_texture.c

@@ -701,7 +701,8 @@ static bool si_texture_get_handle(struct pipe_screen *screen, struct pipe_contex
        * disable it for external clients that want write
        * access.
        */
-      if ((usage & PIPE_HANDLE_USAGE_SHADER_WRITE && !tex->is_depth && tex->surface.meta_offset) ||
+      if (sscreen->debug_flags & DBG(NO_EXPORTED_DCC) ||
+          (usage & PIPE_HANDLE_USAGE_SHADER_WRITE && !tex->is_depth && tex->surface.meta_offset) ||
           /* Displayable DCC requires an explicit flush. */
           (!(usage & PIPE_HANDLE_USAGE_EXPLICIT_FLUSH) &&
            si_displayable_dcc_needs_explicit_flush(tex))) {