[PATCH] glamor: Use GL_STREAM_READ also for read/write access to a PBO

[Michel Dänzer]

From: Michel Dänzer <michel.daenzer at amd.com>

Otherwise the CPU may end up reading from non-cacheable memory, which is
very slow.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=84178
Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
---

Keeping gl_usage in case we need to add back GLAMOR_ACCESS_WO.

 glamor/glamor_prepare.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/glamor/glamor_prepare.c b/glamor/glamor_prepare.c
index 561c55d..fb85d90 100644
--- a/glamor/glamor_prepare.c
+++ b/glamor/glamor_prepare.c
@@ -84,10 +84,7 @@ glamor_prep_pixmap_box(PixmapPtr pixmap, glamor_access_t access, BoxPtr box)
             if (priv->base.pbo == 0)
                 glGenBuffers(1, &priv->base.pbo);
 
-            if (access == GLAMOR_ACCESS_RW)
-                gl_usage = GL_DYNAMIC_DRAW;
-            else
-                gl_usage = GL_STREAM_READ;
+            gl_usage = GL_STREAM_READ;
 
             glBindBuffer(GL_PIXEL_PACK_BUFFER, priv->base.pbo);
             glBufferData(GL_PIXEL_PACK_BUFFER,
-- 
2.1.1