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From: Jun Chen <ptchentw@gmail.com>
To: laurent.pinchart@ideasonboard.com
Cc: mchehab@kernel.org, linux-media@vger.kernel.org,
	linux-kernel@vger.kernel.org, ptchentw@gmail.com,
	Jun Chen <jun.chen@vatics.com>
Subject: [PATCH] media: uvcvideo: Fix annotation for uvc_video_clock_update()
Date: Wed, 25 Dec 2019 10:34:17 +0800	[thread overview]
Message-ID: <1577241257-9203-1-git-send-email-ptchentw@gmail.com> (raw)

From: Jun Chen <jun.chen@vatics.com>

The formula (2) is to convert from SOF to host clock,
it should be fix as
"TS = ((TS2 - TS1) * SOF + TS1 * SOF2 - TS2 * SOF1) / (SOF2 - SOF1)"

Signed-off-by: Jun Chen <jun.chen@vatics.com>
---
 drivers/media/usb/uvc/uvc_video.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index 8fa77a8..a3150da 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -622,7 +622,7 @@ static u16 uvc_video_clock_host_sof(const struct uvc_clock_sample *sample)
  * to avoid losing precision in the division. Similarly, the host timestamp is
  * computed with
  *
- * TS = ((TS2 - TS1) * PTS + TS1 * SOF2 - TS2 * SOF1) / (SOF2 - SOF1)	     (2)
+ * TS = ((TS2 - TS1) * SOF + TS1 * SOF2 - TS2 * SOF1) / (SOF2 - SOF1)	     (2)
  *
  * SOF values are coded on 11 bits by USB. We extend their precision with 16
  * decimal bits, leading to a 11.16 coding.
-- 
1.9.1


             reply	other threads:[~2019-12-25  2:36 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-25  2:34 Jun Chen [this message]
2020-01-01 17:28 ` Laurent Pinchart

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