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* [PATCH] drm/msm: Avoid rounding up to one jiffy
@ 2025-01-09 23:07 Rob Clark
  2025-01-13 10:33 ` Akhil P Oommen
  0 siblings, 1 reply; 2+ messages in thread
From: Rob Clark @ 2025-01-09 23:07 UTC (permalink / raw)
  To: dri-devel
  Cc: freedreno, linux-arm-msm, Rob Clark, Rob Clark, Abhinav Kumar,
	Dmitry Baryshkov, Sean Paul, Marijn Suijten, David Airlie,
	Simona Vetter, open list

From: Rob Clark <robdclark@chromium.org>

If userspace is trying to achieve a timeout of zero, let 'em have it.
Only round up if the timeout is greater than zero.

Fixes: 4969bccd5f4e ("drm/msm: Avoid rounding down to zero jiffies")
Signed-off-by: Rob Clark <robdclark@chromium.org>
---
 drivers/gpu/drm/msm/msm_drv.h | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
index fee31680a6d5..451d258b9827 100644
--- a/drivers/gpu/drm/msm/msm_drv.h
+++ b/drivers/gpu/drm/msm/msm_drv.h
@@ -537,16 +537,14 @@ static inline int align_pitch(int width, int bpp)
 static inline unsigned long timeout_to_jiffies(const ktime_t *timeout)
 {
 	ktime_t now = ktime_get();
-	s64 remaining_jiffies;
 
-	if (ktime_compare(*timeout, now) < 0) {
-		remaining_jiffies = 0;
+	if (ktime_compare(*timeout, now) <= 0) {
+		return 0;
 	} else {
 		ktime_t rem = ktime_sub(*timeout, now);
-		remaining_jiffies = ktime_divns(rem, NSEC_PER_SEC / HZ);
+		s64 remaining_jiffies = ktime_divns(rem, NSEC_PER_SEC / HZ);
+		return clamp(remaining_jiffies, 1LL, (s64)INT_MAX);
 	}
-
-	return clamp(remaining_jiffies, 1LL, (s64)INT_MAX);
 }
 
 /* Driver helpers */
-- 
2.47.1


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