Re: [RFC PATCH 2/2] bttv: fix audio mute on device close for the radio device node

[Mauro Carvalho Chehab <mchehab@redhat.com>]

Em Sun, 10 Mar 2013 14:47:48 +0100
Frank Schäfer <fschaefer.oss@googlemail.com> escreveu:

> Am 10.03.2013 12:59, schrieb Hans Verkuil:
> > On Sun March 10 2013 12:40:35 Frank Schäfer wrote:
> >> Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
> >> ---
> >>  drivers/media/pci/bt8xx/bttv-driver.c |    5 ++++-
> >>  1 Datei geändert, 4 Zeilen hinzugefügt(+), 1 Zeile entfernt(-)
> >>
> >> diff --git a/drivers/media/pci/bt8xx/bttv-driver.c b/drivers/media/pci/bt8xx/bttv-driver.c
> >> index 2c09bc5..74977f7 100644
> >> --- a/drivers/media/pci/bt8xx/bttv-driver.c
> >> +++ b/drivers/media/pci/bt8xx/bttv-driver.c
> >> @@ -3227,6 +3227,7 @@ static int radio_open(struct file *file)
> >>  	v4l2_fh_init(&fh->fh, vdev);
> >>  
> >>  	btv->radio_user++;
> >> +	audio_mute(btv, btv->mute);
> >>  
> >>  	v4l2_fh_add(&fh->fh);
> >>  
> >> @@ -3248,8 +3249,10 @@ static int radio_release(struct file *file)
> >>  
> >>  	bttv_call_all(btv, core, ioctl, SAA6588_CMD_CLOSE, &cmd);
> >>  
> >> -	if (btv->radio_user == 0)
> >> +	if (btv->radio_user == 0) {
> >>  		btv->has_radio_tuner = 0;
> >> +		audio_mute(btv, 1);
> >> +	}
> >>  	return 0;
> >>  }
> >>  
> >>
> > Sorry, but this isn't right.
> >
> > You should be able to just set the radio to a frequency and then exit. Since
> > most cards have an audio out that loops to an audio input you don't want to
> > have to keep the radio device open.
> 
> Ok, so I will drop this patch.
> 
> AFAICS the above said also applies to the video device part, so it's
> still not clear to me why both devices should be handled differently.
> Anyway, I will regard it as a kind of "tradition".

It is not tradition. Changing it would break userspace. For example, xawtv's
"radio" program expects this behavior (see the "-q" and "-m" parameters).

A typical radio usage is to do:

	$ radio -f 93.7 -q

And when user is done listening to radio:

	$ radio -m

Of course, for the above to work, the user needs to have a board wired into
the audio device, or with an speaker directly connected into it.

Regards,
Mauro