[Mesa-dev] [PATCH 1/2] st/wgl: check for negative delta in wait_swap_interval()
Brian Paul
brianp at vmware.com
Wed Aug 16 13:22:57 UTC 2017
From: Frank Richter <frank.richter at dynardo.de>
This can happen because of rollover. See bug report for details.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102241
Cc: mesa-stable at lists.freedesktop.org
Reviewed-by: Brian Paul <brianp at vmware.com>
---
src/gallium/state_trackers/wgl/stw_framebuffer.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/src/gallium/state_trackers/wgl/stw_framebuffer.c b/src/gallium/state_trackers/wgl/stw_framebuffer.c
index 321fbb6..06b5c8d 100644
--- a/src/gallium/state_trackers/wgl/stw_framebuffer.c
+++ b/src/gallium/state_trackers/wgl/stw_framebuffer.c
@@ -601,8 +601,11 @@ wait_swap_interval(struct stw_framebuffer *fb)
int64_t min_swap_period =
1.0e6 / stw_dev->refresh_rate * stw_dev->swap_interval;
- /* if time since last swap is less than wait period, wait */
- if (delta < min_swap_period) {
+ /* If time since last swap is less than wait period, wait.
+ * Note that it's possible for the delta to be negative because of
+ * rollover. See https://bugs.freedesktop.org/show_bug.cgi?id=102241
+ */
+ if ((delta >= 0) && (delta < min_swap_period)) {
float fudge = 1.75f; /* emperical fudge factor */
int64_t wait = (min_swap_period - delta) * fudge;
os_time_sleep(wait);
--
1.9.1
More information about the mesa-dev
mailing list