r200: fix fbo rendering by disabling optimized texture format chooser

It is rather unfortunate that we don't know if a texture is going to be used
as a rt later, and we lack the means to do something about a format chosen
which we can't render to directly, so disable this and always chose renderable
format for rgba8 textures.
This addresses an issue raised on (old) bug,
https://bugs.freedesktop.org/show_bug.cgi?id=51658 with gnome-shell, don't
know if that's still applicable but it might fix other things as well.

Acked-by: Marek Olšák <marek.olsak@amd.com>

diff --git a/src/mesa/drivers/dri/radeon/radeon_texture.c b/src/mesa/drivers/dri/radeon/radeon_texture.c
index 1a178988b68c69885e7b93a3dc64eca38e651171..d05c870128cbbf3b645a9db74ba1c9dc001a2939 100644 (file)
--- a/src/mesa/drivers/dri/radeon/radeon_texture.c
+++ b/src/mesa/drivers/dri/radeon/radeon_texture.c
@@ -224,7 +224,19 @@ static mesa_format radeonChoose8888TexFormat(radeonContextPtr rmesa,
        const GLuint ui = 1;
        const GLubyte littleEndian = *((const GLubyte *)&ui);
 
-       if (fbo)
+
+       /* Unfortunately, regardless the fbo flag, we might still be asked to
+        * attach a texture to a fbo later, which then won't succeed if we chose
+        * one which isn't renderable. And unlike more exotic formats, apps aren't
+        * really prepared for the incomplete framebuffer this results in (they'd
+        * have to retry with same internalFormat even, just different
+        * srcFormat/srcType, which can't really be expected anyway).
+        * Ideally, we'd defer format selection until later (if the texture is
+        * used as a rt it's likely there's never data uploaded to it before attached
+        * to a fbo), but this isn't really possible, so for now just always use
+        * a renderable format.
+        */
+       if (1 || fbo)
                return _radeon_texformat_argb8888;
 
        if ((srcFormat == GL_RGBA && srcType == GL_UNSIGNED_INT_8_8_8_8) ||