[PATCH xserver/dri2 3/3] DRI2SwapBuffers: Return SBC correctly, handle target_msc correctly.

[Jesse Barnes]

On Sun, 21 Feb 2010 05:26:01 +0100
Mario Kleiner <mario.kleiner at tuebingen.mpg.de> wrote:

> Returns expected SBC after completion of swap to caller, as required
> by OML_sync_control spec, instead of the last_swap_target value.
> 
> Passes target_msc, divisor, remainder, correctly for
> glXSwapBuffersMscOML() call, while retaining old
> behaviour for simple glXSwapBuffers() call.
> 
> Signed-off-by: Mario Kleiner <mario.kleiner at tuebingen.mpg.de>

I think this is what it ought to look like on top of my last patch to
fix last_swap_target initialization.

Your other patches looked fine too.

diff --git a/hw/xfree86/dri2/dri2.c b/hw/xfree86/dri2/dri2.c
index 55846b1..952e493 100644
--- a/hw/xfree86/dri2/dri2.c
+++ b/hw/xfree86/dri2/dri2.c
@@ -622,11 +622,26 @@ DRI2SwapBuffers(ClientPtr client, DrawablePtr pDraw, CARD64 target_msc,
     }
 
     /*
-     * Swap target for this swap is last swap target + swap interval since
-     * we have to account for the current swap count, interval, and the
-     * number of pending swaps.
+     * In the simple glXSwapBuffers case, all params will be 0, and we just
+     * need to schedule a swap for the last swap target + the swap interval.
      */
-    *swap_target = pPriv->last_swap_target + pPriv->swap_interval;
+    if (target_msc == 0 && divisor == 0 && remainder == 0) {
+	/*
+	 * Swap target for this swap is last swap target + swap interval since
+	 * we have to account for the current swap count, interval, and the
+	 * number of pending swaps.
+	 */
+	*swap_target = pPriv->last_swap_target + pPriv->swap_interval;
+    } else {
+	/* glXSwapBuffersMscOML() call with target_msc, divisor, remainder set.
+	 * Just make sure that target_msc is not earlier than last swap target +
+	 * swap interval.
+	 */
+	if (target_msc < pPriv->last_swap_target + pPriv->swap_interval)
+	    target_msc = pPriv->last_swap_target + pPriv->swap_interval;
+
+	*swap_target = target_msc;
+    }
 
     ret = (*ds->ScheduleSwap)(client, pDraw, pDestBuffer, pSrcBuffer,
 			      swap_target, divisor, remainder, func, data);
@@ -639,6 +654,11 @@ DRI2SwapBuffers(ClientPtr client, DrawablePtr pDraw, CARD64 target_msc,
     pPriv->swapsPending++;
     pPriv->last_swap_target = *swap_target;
 
+    /* According to spec, return expected swapbuffers count SBC after this swap
+     * will complete.
+     */
+    *swap_target = pPriv->swap_count + pPriv->swapsPending;
+
     return Success;
 }