* [PATCH] media: uvcvideo: Fix annotation for uvc_video_clock_update()
@ 2019-12-25 2:34 Jun Chen
2020-01-01 17:28 ` Laurent Pinchart
0 siblings, 1 reply; 2+ messages in thread
From: Jun Chen @ 2019-12-25 2:34 UTC (permalink / raw)
To: laurent.pinchart; +Cc: mchehab, linux-media, linux-kernel, ptchentw, Jun Chen
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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] media: uvcvideo: Fix annotation for uvc_video_clock_update()
2019-12-25 2:34 [PATCH] media: uvcvideo: Fix annotation for uvc_video_clock_update() Jun Chen
@ 2020-01-01 17:28 ` Laurent Pinchart
0 siblings, 0 replies; 2+ messages in thread
From: Laurent Pinchart @ 2020-01-01 17:28 UTC (permalink / raw)
To: Jun Chen; +Cc: mchehab, linux-media, linux-kernel, Jun Chen
Hello Jun,
Thank you for the patch.
On Wed, Dec 25, 2019 at 10:34:17AM +0800, Jun Chen wrote:
> 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>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
and applied to my tree.
> ---
> 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.
--
Regards,
Laurent Pinchart
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