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* [PATCH] [RESEND] vmwgfx: use monotonic event timestamps
@ 2018-01-16 17:18 ` Arnd Bergmann
  0 siblings, 0 replies; 11+ messages in thread
From: Arnd Bergmann @ 2018-01-16 17:18 UTC (permalink / raw)
  To: VMware Graphics, Sinclair Yeh, Thomas Hellstrom, David Airlie
  Cc: y2038, Arnd Bergmann, Deepak Singh Rawat, Patrik Jakobsson,
	Alex Deucher, Arvind Yadav, dri-devel, linux-kernel

DRM_VMW_EVENT_FENCE_SIGNALED (struct drm_vmw_event_fence) and
DRM_EVENT_VBLANK (struct drm_event_vblank) pass timestamps in 32-bit
seconds/microseconds format.

As of commit c61eef726a78 ("drm: add support for monotonic vblank
timestamps"), other DRM drivers use monotonic times for drm_event_vblank,
but vmwgfx still uses CLOCK_REALTIME for both events, which suffers from
the y2038/y2106 overflow as well as time jumps.

For consistency, this changes vmwgfx to use ktime_get_ts64 as well,
which solves those problems and avoids the deprecated do_gettimeofday()
function.

This should be transparent to to user space, as long as it doesn't
compare the time against the result of gettimeofday().

Link: https://patchwork.kernel.org/patch/10076599/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
Originally sent on Nov 27. Sinclair Yeh said he'd pick it up
for the next pull request, but it's not in linux-next yet.

Resending the unchanged patch, please pick it up when you have time,
or feel free to ignore this email in case it's already in some tree
that just isn't part of linux-next but will be sent during the
next merge window.
---
 drivers/gpu/drm/vmwgfx/vmwgfx_fence.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
index 6c5c75cf5e6c..9ed544f8958f 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
@@ -901,11 +901,12 @@ static void vmw_event_fence_action_seq_passed(struct vmw_fence_action *action)
 	spin_lock_irq(&dev->event_lock);
 
 	if (likely(eaction->tv_sec != NULL)) {
-		struct timeval tv;
+		struct timespec64 ts;
 
-		do_gettimeofday(&tv);
-		*eaction->tv_sec = tv.tv_sec;
-		*eaction->tv_usec = tv.tv_usec;
+		ktime_get_ts64(&ts);
+		/* monotonic time, so no y2038 overflow */
+		*eaction->tv_sec = ts.tv_sec;
+		*eaction->tv_usec = ts.tv_nsec / NSEC_PER_USEC;
 	}
 
 	drm_send_event_locked(dev, eaction->event);
-- 
2.9.0

^ permalink raw reply related	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2018-01-17  8:28 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-01-16 17:18 [PATCH] [RESEND] vmwgfx: use monotonic event timestamps Arnd Bergmann
2018-01-16 17:18 ` Arnd Bergmann
2018-01-16 17:28 ` Thomas Hellstrom
2018-01-16 17:28   ` Thomas Hellstrom
2018-01-16 21:39   ` Woody Suwalski
2018-01-16 21:39     ` Woody Suwalski
2018-01-17  6:33     ` drm: fix vmwgfx boot warning WAS " Thomas Hellstrom
2018-01-17  6:33       ` Thomas Hellstrom
2018-01-17  8:19       ` Thomas Hellstrom
2018-01-17  8:19         ` Thomas Hellstrom
2018-01-16 21:53   ` Arnd Bergmann

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