st/dri: Set render_buffer in dri_fill_st_visual

st/mesa/st_managaer.c needs render_buffer in order
to determinde which buffer should be rendered to.

diff --git a/src/gallium/state_trackers/dri/common/dri_screen.c b/src/gallium/state_trackers/dri/common/dri_screen.c
index f6e22c7..69c2e7e 100644 (file)
--- a/src/gallium/state_trackers/dri/common/dri_screen.c
+++ b/src/gallium/state_trackers/dri/common/dri_screen.c
@@ -235,7 +235,6 @@ dri_fill_st_visual(struct st_visual *stvis, struct dri_screen *screen,
       return;
 
    stvis->samples = mode->samples;
-   stvis->render_buffer = ST_ATTACHMENT_INVALID;
 
    if (mode->redBits == 8) {
       if (mode->alphaBits == 8)
@@ -274,8 +273,11 @@ dri_fill_st_visual(struct st_visual *stvis, struct dri_screen *screen,
       PIPE_FORMAT_R16G16B16A16_SNORM : PIPE_FORMAT_NONE;
 
    stvis->buffer_mask |= ST_ATTACHMENT_FRONT_LEFT_MASK;
-   if (mode->doubleBufferMode)
+   stvis->render_buffer = ST_ATTACHMENT_FRONT_LEFT;
+   if (mode->doubleBufferMode) {
       stvis->buffer_mask |= ST_ATTACHMENT_BACK_LEFT_MASK;
+      stvis->render_buffer = ST_ATTACHMENT_BACK_LEFT;
+   }
    if (mode->stereoMode) {
       stvis->buffer_mask |= ST_ATTACHMENT_FRONT_RIGHT_MASK;
       if (mode->doubleBufferMode)