DRI2: Add fake front-buffer to request list for windows

If a front-buffer is requested for a window, add the fake front-buffer
to the list of requested buffers.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
(cherry picked from commit aa2928325fe51d94a636dde9c090e8f54a311a12)

1 files changed, 40 insertions, 0 deletions

diff --git a/hw/xfree86/dri2/dri2.c b/hw/xfree86/dri2/dri2.c
index 0f2e24b3f..351d02b7b 100644
--- a/hw/xfree86/dri2/dri2.c
+++ b/hw/xfree86/dri2/dri2.c
@@ -139,6 +139,42 @@ DRI2GetBuffers(DrawablePtr pDraw, int *width, int *height,
     DRI2ScreenPtr   ds = DRI2GetScreen(pDraw->pScreen);
     DRI2DrawablePtr pPriv = DRI2GetDrawable(pDraw);
     DRI2BufferPtr   buffers;
+    unsigned int temp_buf[32];
+    unsigned int *temp = temp_buf;
+
+
+    /* If the drawable is a window and the front-buffer is requested, silently
+     * add the fake front-buffer to the list of requested attachments.  The
+     * counting logic in the loop accounts for the case where the client
+     * requests both the fake and real front-buffer.
+     */
+    if (pDraw->type == DRAWABLE_WINDOW) {
+	int need_fake_front = 0;
+	int i;
+
+	if ((count + 1) > 32) {
+	    temp = xalloc((count + 1) * sizeof(temp[0]));
+	}
+
+	for (i = 0; i < count; i++) {
+	    if (attachments[i] == DRI2BufferFrontLeft) {
+		need_fake_front++;
+	    }
+
+	    if (attachments[i] == DRI2BufferFakeFrontLeft) {
+		need_fake_front--;
+	    }
+
+	    temp[i] = attachments[i];
+	}
+
+	if (need_fake_front > 0) {
+	    temp[i] = DRI2BufferFakeFrontLeft;
+	    count++;
+	    attachments = temp;
+	}
+    }
+
 
     if (pPriv->buffers == NULL ||
 	pDraw->width != pPriv->width || pDraw->height != pPriv->height)
@@ -151,6 +187,10 @@ DRI2GetBuffers(DrawablePtr pDraw, int *width, int *height,
 	pPriv->height = pDraw->height;
     }
 
+    if (temp != temp_buf) {
+	xfree(temp);
+    }
+
     *width = pPriv->width;
     *height = pPriv->height;
     *out_count = pPriv->bufferCount;