[Mesa-dev] [PATCH 2/6] i965: Add a RGBX->RGBA fallback for glEGLImageTextureTarget2D()

[Chad Versace]

This enables support for importing RGBX8888 EGLImage textures on
Skylake.

Chrome OS needs support for RGBX8888 EGLImage textures because because
the Android framework produces HAL_PIXEL_FORMAT_RGBX8888 winsys
surfaces, which the Chrome OS compositor consumes as dma_bufs.  On
hardware for which RGBX is unsupported or disabled, normally core Mesa
provides the RGBX->RGBA fallback during glTexStorage.  But the DRIimage
code bypasses core Mesa, so we must do the fallback in i965.
---
 src/mesa/drivers/dri/i965/intel_tex_image.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/intel_tex_image.c b/src/mesa/drivers/dri/i965/intel_tex_image.c
index 649b3907d1..92c6c15c72 100644
--- a/src/mesa/drivers/dri/i965/intel_tex_image.c
+++ b/src/mesa/drivers/dri/i965/intel_tex_image.c
@@ -5,6 +5,7 @@
 #include "main/bufferobj.h"
 #include "main/context.h"
 #include "main/formats.h"
+#include "main/format_fallback.h"
 #include "main/glformats.h"
 #include "main/image.h"
 #include "main/pbo.h"
@@ -254,8 +255,22 @@ create_mt_for_dri_image(struct brw_context *brw,
    struct gl_context *ctx = &brw->ctx;
    struct intel_mipmap_tree *mt;
    uint32_t draw_x, draw_y;
+   mesa_format format = image->format;
+
+   if (!ctx->TextureFormatSupported[format]) {
+      /* The texture storage paths in core Mesa detect if the driver does not
+       * support the user-requested format, and then searches for a
+       * fallback format. The DRIimage code bypasses core Mesa, though. So we
+       * do the fallbacks here for important formats.
+       *
+       * We must support DRM_FOURCC_XBGR8888 textures because the Android
+       * framework produces HAL_PIXEL_FORMAT_RGBX8888 winsys surfaces, which
+       * the Chrome OS compositor consumes as dma_buf EGLImages.
+       */
+      format = _mesa_format_fallback_rgbx_to_rgba(format);
+   }
 
-   if (!ctx->TextureFormatSupported[image->format])
+   if (!ctx->TextureFormatSupported[format])
       return NULL;
 
    /* Disable creation of the texture's aux buffers because the driver exposes
@@ -263,7 +278,7 @@ create_mt_for_dri_image(struct brw_context *brw,
     * buffer's content to the main buffer nor for invalidating the aux buffer's
     * content.
     */
-   mt = intel_miptree_create_for_bo(brw, image->bo, image->format,
+   mt = intel_miptree_create_for_bo(brw, image->bo, format,
                                     0, image->width, image->height, 1,
                                     image->pitch,
                                     MIPTREE_LAYOUT_DISABLE_AUX);
-- 
2.13.0