glx: Handle out-of-sequence swap completion events correctly. (v2)

[mesa.git] / src / glx / glxext.c

diff --git a/src/glx/glxext.c b/src/glx/glxext.c
index 68c359e6e2c78d7fedc089610b89682fb5acd788..fdc24d439c13dd556d3952c31b12609f31e60d2f 100644 (file)
--- a/src/glx/glxext.c
+++ b/src/glx/glxext.c
@@ -143,8 +143,13 @@ __glXWireToEvent(Display *dpy, XEvent *event, xEvent *wire)
       aevent->ust = ((CARD64)awire->ust_hi << 32) | awire->ust_lo;
       aevent->msc = ((CARD64)awire->msc_hi << 32) | awire->msc_lo;
 
-      if (awire->sbc < glxDraw->lastEventSbc)
-        glxDraw->eventSbcWrap += 0x100000000;
+      /* Handle 32-Bit wire sbc wraparound in both directions to cope with out
+       * of sequence 64-Bit sbc's
+       */
+      if ((int64_t) awire->sbc < ((int64_t) glxDraw->lastEventSbc - 0x40000000))
+         glxDraw->eventSbcWrap += 0x100000000;
+      if ((int64_t) awire->sbc > ((int64_t) glxDraw->lastEventSbc + 0x40000000))
+         glxDraw->eventSbcWrap -= 0x100000000;
       glxDraw->lastEventSbc = awire->sbc;
       aevent->sbc = awire->sbc + glxDraw->eventSbcWrap;
       return True;