Hi Hans,
On Monday 18 June 2012 13:40:24 Hans Verkuil wrote:
> On Mon June 18 2012 12:01:47 Laurent Pinchart wrote:
> > On Sunday 10 June 2012 12:25:51 Hans Verkuil wrote:
> > > From: Hans Verkuil <hans.verk...@cisco.com>
> > >
> > > Signed-off-by: Hans Verkuil <hans.verk...@cisco.com>
> > > ---
> > >
> > > drivers/media/video/v4l2-dev.c | 41 ++++++++++++++++++++++-----------
> > > 1 file changed, 29 insertions(+), 12 deletions(-)
> > >
> > > diff --git a/drivers/media/video/v4l2-dev.c
> > > b/drivers/media/video/v4l2-dev.c index 5c0bb18..54f387d 100644
> > > --- a/drivers/media/video/v4l2-dev.c
> > > +++ b/drivers/media/video/v4l2-dev.c
> > > @@ -305,6 +305,9 @@ static ssize_t v4l2_read(struct file *filp, char
> > > __user
> > > *buf, ret = vdev->fops->read(filp, buf, sz, off);
> > >
> > > if (test_bit(V4L2_FL_LOCK_ALL_FOPS, &vdev->flags))
> > >
> > > mutex_unlock(vdev->lock);
> > >
> > > + if (vdev->debug)
> >
> > As vdev->debug is a bitmask, shouldn't we add an fops debug bit ?
>
> I actually want to move away from the bitmask idea. I've never really liked
> it here.
Would using dev_dbg with dynamic printk instead of creating our own logging
system be an option ?
> > > + pr_info("%s: read: %zd (%d)\n",
> > > + video_device_node_name(vdev), sz, ret);
> >
> > Shouldn't we use KERN_DEBUG instead of KERN_INFO ? BTW, what about
> > replacing the pr_* calls with dev_* calls ?
>
> KERN_DEBUG vs KERN_INFO is actually a good question. My reasoning is that
> you explicitly enable logging, and so you really want to see it in the log,
> so we use KERN_INFO. With KERN_DEBUG you might have the situation where the
> debug level of the logging is disabled, so the messages are ignored.
>
> However, if people disagree with this, then I'm happy to move it back to
> KERN_DEBUG.
On embedded systems KERN_INFO will be printed to the serial console.
Interleaving kernel messages with application output during capture result in
a mess.
If someone enables debugging I expect him/her to know enough to get the kernel
log debug messages.
> With regards to dev_ vs pr_: I'd have to test this to see what dev_ prints
> as prefix.
--
Regards,
Laurent Pinchart
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