Hi Hans,

I'm sorry for the delay.

This series still sounds useful, so let's try to
revive it.

On Mon, 2019-03-11 at 12:16 +0100, Hans Verkuil wrote:
> On 2/27/19 6:07 PM, Ezequiel Garcia wrote:
> > In preparation to cleanup the debug logic, simplify the dev_debug
> > usage. In particular, make sure that a single flag is used to
> > control each debug print.
> > 
> > Before this commit V4L2_DEV_DEBUG_STREAMING and V4L2_DEV_DEBUG_FOP
> > were needed to enable read and write debugging. After this commit
> > only the former is needed.
> 
> The original idea was that ioctls are logged with V4L2_DEV_DEBUG_IOCTL
> and file ops with V4L2_DEV_DEBUG_FOP. And to see the streaming ioctls
> or fops you would have to add V4L2_DEV_DEBUG_STREAMING in addition to
> DEBUG_IOCTL/FOP.
> 
> This patch changes the behavior in that the streaming fops are now
> solely controlled by V4L2_DEV_DEBUG_STREAMING.
> 
> I do agree with this change, but this requires that the same change is
> done for the streaming ioctls (DQBUF/QBUF) and that the documentation in
> Documentation/media/kapi/v4l2-dev.rst is updated (section "video device
> debugging").
> 

Oops, I managed to somehow miss (D)QBUF, even though it's perfectly
well documented in the header!

Will fix, and will fix the documentation as well.
  
> Of course, the documentation should also mention the new dev_debug
> module parameter and the new debug flag for debugging controls.
> 
> Regards,
> 
>       Hans
> 
> > Signed-off-by: Ezequiel Garcia <[email protected]>
> > ---
> >  drivers/media/v4l2-core/v4l2-dev.c | 6 ++----
> >  1 file changed, 2 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/media/v4l2-core/v4l2-dev.c 
> > b/drivers/media/v4l2-core/v4l2-dev.c
> > index d7528f82a66a..34e4958663bf 100644
> > --- a/drivers/media/v4l2-core/v4l2-dev.c
> > +++ b/drivers/media/v4l2-core/v4l2-dev.c
> > @@ -315,8 +315,7 @@ static ssize_t v4l2_read(struct file *filp, char __user 
> > *buf,
> >             return -EINVAL;
> >     if (video_is_registered(vdev))
> >             ret = vdev->fops->read(filp, buf, sz, off);
> > -   if ((vdev->dev_debug & V4L2_DEV_DEBUG_FOP) &&
> > -       (vdev->dev_debug & V4L2_DEV_DEBUG_STREAMING))
> > +   if (vdev->dev_debug & V4L2_DEV_DEBUG_STREAMING)
> >             dprintk("%s: read: %zd (%d)\n",
> >                     video_device_node_name(vdev), sz, ret);
> >     return ret;
> > @@ -332,8 +331,7 @@ static ssize_t v4l2_write(struct file *filp, const char 
> > __user *buf,
> >             return -EINVAL;
> >     if (video_is_registered(vdev))
> >             ret = vdev->fops->write(filp, buf, sz, off);
> > -   if ((vdev->dev_debug & V4L2_DEV_DEBUG_FOP) &&
> > -       (vdev->dev_debug & V4L2_DEV_DEBUG_STREAMING))
> > +   if (vdev->dev_debug & V4L2_DEV_DEBUG_STREAMING)
> >             dprintk("%s: write: %zd (%d)\n",
> >                     video_device_node_name(vdev), sz, ret);
> >     return ret;
> > 


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