[Mesa-dev] [PATCH] st/mesa: Don't use PIPE_USAGE_STREAM for GL_PIXEL_UNPACK_BUFFER_ARB

[Michel Dänzer]

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

The latter currently implies CPU access, so we have to avoid getting
uncacheable memory.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=88658
Cc: "10.3 10.4" <mesa-stable at lists.freedestkop.org>
Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
---
 src/mesa/state_tracker/st_cb_bufferobjects.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/mesa/state_tracker/st_cb_bufferobjects.c b/src/mesa/state_tracker/st_cb_bufferobjects.c
index 55f3644..90f786c 100644
--- a/src/mesa/state_tracker/st_cb_bufferobjects.c
+++ b/src/mesa/state_tracker/st_cb_bufferobjects.c
@@ -256,8 +256,15 @@ st_bufferobj_data(struct gl_context *ctx,
          break;
       case GL_STREAM_DRAW:
       case GL_STREAM_COPY:
-         pipe_usage = PIPE_USAGE_STREAM;
-         break;
+         /* XXX: Remove this test and fall-through when we have PBO unpacking
+          * acceleration. Right now, PBO unpacking is done by the CPU, so we
+          * have to make sure CPU reads are fast.
+          */
+         if (target != GL_PIXEL_UNPACK_BUFFER_ARB) {
+            pipe_usage = PIPE_USAGE_STREAM;
+            break;
+         }
+         /* fall through */
       case GL_STATIC_READ:
       case GL_DYNAMIC_READ:
       case GL_STREAM_READ:
-- 
2.1.4