* [PATCH] media: uvcvideo: Return queued buffers on start_streaming() failure
@ 2025-10-15 11:36 Michal Pecio
2025-10-21 10:47 ` Ricardo Ribalda Delgado
0 siblings, 1 reply; 3+ messages in thread
From: Michal Pecio @ 2025-10-15 11:36 UTC (permalink / raw)
To: Laurent Pinchart, Hans de Goede, Mauro Carvalho Chehab
Cc: Hans Verkuil, Ricardo Ribalda, linux-media, linux-kernel
Return buffers if streaming fails to start due to uvc_pm_get() error.
This bug may be responsible for a warning I got running
while :; do yavta -c3 /dev/video0; done
on an xHCI controller which failed under this workload.
I had no luck reproducing this warning again to confirm.
xhci_hcd 0000:09:00.0: HC died; cleaning up
usb 13-2: USB disconnect, device number 2
WARNING: CPU: 2 PID: 29386 at drivers/media/common/videobuf2/videobuf2-core.c:1803 vb2_start_streaming+0xac/0x120
Fixes: 7dd56c47784a ("media: uvcvideo: Remove stream->is_streaming field")
Cc: stable@vger.kernel.org
Signed-off-by: Michal Pecio <michal.pecio@gmail.com>
---
drivers/media/usb/uvc/uvc_queue.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/media/usb/uvc/uvc_queue.c b/drivers/media/usb/uvc/uvc_queue.c
index 790184c9843d..f49c538618bc 100644
--- a/drivers/media/usb/uvc/uvc_queue.c
+++ b/drivers/media/usb/uvc/uvc_queue.c
@@ -177,7 +177,7 @@ static int uvc_start_streaming_video(struct vb2_queue *vq, unsigned int count)
ret = uvc_pm_get(stream->dev);
if (ret)
- return ret;
+ goto return_buffers;
queue->buf_used = 0;
@@ -187,6 +187,7 @@ static int uvc_start_streaming_video(struct vb2_queue *vq, unsigned int count)
uvc_pm_put(stream->dev);
+return_buffers:
uvc_queue_return_buffers(queue, UVC_BUF_STATE_QUEUED);
return ret;
--
2.48.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] media: uvcvideo: Return queued buffers on start_streaming() failure
2025-10-15 11:36 [PATCH] media: uvcvideo: Return queued buffers on start_streaming() failure Michal Pecio
@ 2025-10-21 10:47 ` Ricardo Ribalda Delgado
2025-11-13 21:37 ` Laurent Pinchart
0 siblings, 1 reply; 3+ messages in thread
From: Ricardo Ribalda Delgado @ 2025-10-21 10:47 UTC (permalink / raw)
To: Michal Pecio
Cc: Laurent Pinchart, Hans de Goede, Mauro Carvalho Chehab,
Hans Verkuil, Ricardo Ribalda, linux-media, linux-kernel
Hi Michal
It seems that the device was disconnected while doing streamon. That
caused uvc_pm_get() to fail and exit without returning the buffers.
Your patch is not going to help to fix:
xhci_hcd 0000:09:00.0: HC died; cleaning up
usb 13-2: USB disconnect, device number 2
But it is fixing an issue. thanks :)
On Wed, Oct 15, 2025 at 1:36 PM Michal Pecio <michal.pecio@gmail.com> wrote:
>
> Return buffers if streaming fails to start due to uvc_pm_get() error.
>
> This bug may be responsible for a warning I got running
>
> while :; do yavta -c3 /dev/video0; done
>
> on an xHCI controller which failed under this workload.
> I had no luck reproducing this warning again to confirm.
>
> xhci_hcd 0000:09:00.0: HC died; cleaning up
> usb 13-2: USB disconnect, device number 2
> WARNING: CPU: 2 PID: 29386 at drivers/media/common/videobuf2/videobuf2-core.c:1803 vb2_start_streaming+0xac/0x120
>
> Fixes: 7dd56c47784a ("media: uvcvideo: Remove stream->is_streaming field")
> Cc: stable@vger.kernel.org
> Signed-off-by: Michal Pecio <michal.pecio@gmail.com>
Reviewed-by: Ricardo Ribalda <ribalda@chromium.org>
> ---
> drivers/media/usb/uvc/uvc_queue.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_queue.c b/drivers/media/usb/uvc/uvc_queue.c
> index 790184c9843d..f49c538618bc 100644
> --- a/drivers/media/usb/uvc/uvc_queue.c
> +++ b/drivers/media/usb/uvc/uvc_queue.c
> @@ -177,7 +177,7 @@ static int uvc_start_streaming_video(struct vb2_queue *vq, unsigned int count)
>
> ret = uvc_pm_get(stream->dev);
> if (ret)
> - return ret;
> + goto return_buffers;
>
> queue->buf_used = 0;
>
> @@ -187,6 +187,7 @@ static int uvc_start_streaming_video(struct vb2_queue *vq, unsigned int count)
>
> uvc_pm_put(stream->dev);
>
> +return_buffers:
> uvc_queue_return_buffers(queue, UVC_BUF_STATE_QUEUED);
>
> return ret;
> --
> 2.48.1
>
--
Ricardo Ribalda
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] media: uvcvideo: Return queued buffers on start_streaming() failure
2025-10-21 10:47 ` Ricardo Ribalda Delgado
@ 2025-11-13 21:37 ` Laurent Pinchart
0 siblings, 0 replies; 3+ messages in thread
From: Laurent Pinchart @ 2025-11-13 21:37 UTC (permalink / raw)
To: Ricardo Ribalda Delgado
Cc: Michal Pecio, Hans de Goede, Mauro Carvalho Chehab, Hans Verkuil,
Ricardo Ribalda, linux-media, linux-kernel
On Tue, Oct 21, 2025 at 12:47:23PM +0200, Ricardo Ribalda Delgado wrote:
> Hi Michal
>
> It seems that the device was disconnected while doing streamon. That
> caused uvc_pm_get() to fail and exit without returning the buffers.
>
> Your patch is not going to help to fix:
> xhci_hcd 0000:09:00.0: HC died; cleaning up
> usb 13-2: USB disconnect, device number 2
>
> But it is fixing an issue. thanks :)
>
> On Wed, Oct 15, 2025 at 1:36 PM Michal Pecio <michal.pecio@gmail.com> wrote:
> >
> > Return buffers if streaming fails to start due to uvc_pm_get() error.
> >
> > This bug may be responsible for a warning I got running
> >
> > while :; do yavta -c3 /dev/video0; done
> >
> > on an xHCI controller which failed under this workload.
> > I had no luck reproducing this warning again to confirm.
> >
> > xhci_hcd 0000:09:00.0: HC died; cleaning up
> > usb 13-2: USB disconnect, device number 2
> > WARNING: CPU: 2 PID: 29386 at drivers/media/common/videobuf2/videobuf2-core.c:1803 vb2_start_streaming+0xac/0x120
> >
> > Fixes: 7dd56c47784a ("media: uvcvideo: Remove stream->is_streaming field")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Michal Pecio <michal.pecio@gmail.com>
> Reviewed-by: Ricardo Ribalda <ribalda@chromium.org>
>
> > ---
> > drivers/media/usb/uvc/uvc_queue.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/usb/uvc/uvc_queue.c b/drivers/media/usb/uvc/uvc_queue.c
> > index 790184c9843d..f49c538618bc 100644
> > --- a/drivers/media/usb/uvc/uvc_queue.c
> > +++ b/drivers/media/usb/uvc/uvc_queue.c
> > @@ -177,7 +177,7 @@ static int uvc_start_streaming_video(struct vb2_queue *vq, unsigned int count)
> >
> > ret = uvc_pm_get(stream->dev);
> > if (ret)
> > - return ret;
> > + goto return_buffers;
> >
> > queue->buf_used = 0;
> >
> > @@ -187,6 +187,7 @@ static int uvc_start_streaming_video(struct vb2_queue *vq, unsigned int count)
> >
> > uvc_pm_put(stream->dev);
> >
> > +return_buffers:
> > uvc_queue_return_buffers(queue, UVC_BUF_STATE_QUEUED);
> >
> > return ret;
Error labels should start with err_. I'd like to take this as an
opportunity to reorganize the error path with something like
ret = uvc_pm_get(stream->dev);
if (ret)
goto err_buffers;
queue->buf_used = 0;
ret = uvc_video_start_streaming(stream);
if (ret)
goto err_pm;
return 0;
err_pm:
uvc_pm_put(stream->dev);
err_buffers:
uvc_queue_return_buffers(queue, UVC_BUF_STATE_QUEUED);
return ret;
I'll send a v2 that does this.
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
--
Regards,
Laurent Pinchart
^ permalink raw reply [flat|nested] 3+ messages in thread
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2025-10-15 11:36 [PATCH] media: uvcvideo: Return queued buffers on start_streaming() failure Michal Pecio
2025-10-21 10:47 ` Ricardo Ribalda Delgado
2025-11-13 21:37 ` Laurent Pinchart
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