Re: [PATCH v2 11/11] media: usb: uvc: use vb2_ops_wait_prepare/finish helper

From: Prabhakar Lad
Date: Wed Nov 26 2014 - 18:18:11 EST


Hi Laurent,

Thanks for the review.

On Wed, Nov 26, 2014 at 10:59 PM, Laurent Pinchart
<laurent.pinchart@xxxxxxxxxxxxxxxx> wrote:
> Hi Prabhakar,
>
> Thank you for the patch.
>
> On Wednesday 26 November 2014 22:42:34 Lad, Prabhakar wrote:
>> This patch drops driver specific wait_prepare() and
>> wait_finish() callbacks from vb2_ops and instead uses
>> the the helpers vb2_ops_wait_prepare/finish() provided
>> by the vb2 core, the lock member of the queue needs
>> to be initalized to a mutex so that vb2 helpers
>> vb2_ops_wait_prepare/finish() can make use of it.
>
> The queue lock field isn't initialized by the uvcvideo driver, so you can't
> use vb2_ops_wait_prepare|finish().
>
Oops not sure what happened here I just took the patch from [1]
and added commit message. anyway will post a single patch v3.

[1] https://patchwork.kernel.org/patch/5327451/

Thanks,
--Prabhakar Lad

>> Signed-off-by: Lad, Prabhakar <prabhakar.csengg@xxxxxxxxx>
>> Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
>> ---
>> drivers/media/usb/uvc/uvc_queue.c | 18 ++----------------
>> 1 file changed, 2 insertions(+), 16 deletions(-)
>>
>> diff --git a/drivers/media/usb/uvc/uvc_queue.c
>> b/drivers/media/usb/uvc/uvc_queue.c index cc96072..64147b5 100644
>> --- a/drivers/media/usb/uvc/uvc_queue.c
>> +++ b/drivers/media/usb/uvc/uvc_queue.c
>> @@ -143,20 +143,6 @@ static void uvc_buffer_finish(struct vb2_buffer *vb)
>> uvc_video_clock_update(stream, &vb->v4l2_buf, buf);
>> }
>>
>> -static void uvc_wait_prepare(struct vb2_queue *vq)
>> -{
>> - struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
>> -
>> - mutex_unlock(&queue->mutex);
>> -}
>> -
>> -static void uvc_wait_finish(struct vb2_queue *vq)
>> -{
>> - struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
>> -
>> - mutex_lock(&queue->mutex);
>> -}
>> -
>> static int uvc_start_streaming(struct vb2_queue *vq, unsigned int count)
>> {
>> struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
>> @@ -195,8 +181,8 @@ static struct vb2_ops uvc_queue_qops = {
>> .buf_prepare = uvc_buffer_prepare,
>> .buf_queue = uvc_buffer_queue,
>> .buf_finish = uvc_buffer_finish,
>> - .wait_prepare = uvc_wait_prepare,
>> - .wait_finish = uvc_wait_finish,
>> + .wait_prepare = vb2_ops_wait_prepare,
>> + .wait_finish = vb2_ops_wait_finish,
>> .start_streaming = uvc_start_streaming,
>> .stop_streaming = uvc_stop_streaming,
>> };
>
> --
> Regards,
>
> Laurent Pinchart
>
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