On Wed, Dec 18, 2024 at 09:39:10PM +0000, Ricardo Ribalda wrote:
> Right now the parameter value is read during video_registration and
> cannot be changed afterwards, despite its permissions 0644, that makes
> the user believe that the value can be written.
Well, it can still be written, and will apply to new devices. There's
value in making it fully dynamic though.
>
> The parameter only affects the beviour of uvc_queue_buffer_complete(),
s/beviour/behaviour/
> with only one check per buffer.
>
> We can read the value directly from uvc_queue_buffer_complete() and
> therefore allowing changing it with sysfs on the fly.
>
> Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
> ---
> drivers/media/usb/uvc/uvc_driver.c | 2 +-
> drivers/media/usb/uvc/uvc_queue.c | 6 ++----
> drivers/media/usb/uvc/uvcvideo.h | 4 +---
> 3 files changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> index 091145743872..10812a841587 100644
> --- a/drivers/media/usb/uvc/uvc_driver.c
> +++ b/drivers/media/usb/uvc/uvc_driver.c
> @@ -1995,7 +1995,7 @@ int uvc_register_video_device(struct uvc_device *dev,
> int ret;
>
> /* Initialize the video buffers queue. */
> - ret = uvc_queue_init(queue, type, !uvc_no_drop_param);
> + ret = uvc_queue_init(queue, type);
> if (ret)
> return ret;
>
> diff --git a/drivers/media/usb/uvc/uvc_queue.c b/drivers/media/usb/uvc/uvc_queue.c
> index f8464f0aae1b..2ee142621042 100644
> --- a/drivers/media/usb/uvc/uvc_queue.c
> +++ b/drivers/media/usb/uvc/uvc_queue.c
> @@ -208,8 +208,7 @@ static const struct vb2_ops uvc_meta_queue_qops = {
> .stop_streaming = uvc_stop_streaming,
> };
>
> -int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
> - int drop_corrupted)
> +int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type)
> {
> int ret;
>
> @@ -239,7 +238,6 @@ int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
> mutex_init(&queue->mutex);
> spin_lock_init(&queue->irqlock);
> INIT_LIST_HEAD(&queue->irqqueue);
> - queue->flags = drop_corrupted ? UVC_QUEUE_DROP_CORRUPTED : 0;
>
> return 0;
> }
> @@ -472,7 +470,7 @@ static void uvc_queue_buffer_complete(struct kref *ref)
> struct vb2_buffer *vb = &buf->buf.vb2_buf;
> struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
>
> - if ((queue->flags & UVC_QUEUE_DROP_CORRUPTED) && buf->error) {
> + if (buf->error && !uvc_no_drop_param) {
As this is the only location where the uvc_no_drop_param variable is
read, I don't expect any race condition.
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> uvc_queue_buffer_requeue(queue, buf);
> return;
> }
> diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> index 07f9921d83f2..ebbd8afcf136 100644
> --- a/drivers/media/usb/uvc/uvcvideo.h
> +++ b/drivers/media/usb/uvc/uvcvideo.h
> @@ -316,7 +316,6 @@ struct uvc_buffer {
> };
>
> #define UVC_QUEUE_DISCONNECTED (1 << 0)
> -#define UVC_QUEUE_DROP_CORRUPTED (1 << 1)
>
> struct uvc_video_queue {
> struct vb2_queue queue;
> @@ -674,8 +673,7 @@ extern struct uvc_driver uvc_driver;
> struct uvc_entity *uvc_entity_by_id(struct uvc_device *dev, int id);
>
> /* Video buffers queue management. */
> -int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
> - int drop_corrupted);
> +int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type);
> void uvc_queue_release(struct uvc_video_queue *queue);
> int uvc_request_buffers(struct uvc_video_queue *queue,
> struct v4l2_requestbuffers *rb);
--
Regards,
Laurent Pinchart
