On Sun March 10 2013 14:47:48 Frank Schäfer wrote:
> 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....@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 legacy. I doubt we would design it like that today. Also note that
there is generally little point in just listening to TV without actually
watching it (although some people do :-) ), so it makes sense to mute the
audio when you stop watching TV.
But radio has traditionally been implemented this way and we have to keep
that.
Regards,
Hans
>
> >
> > Audio should be muted when the module is unloaded, though.
> >
> > The relationship between TV and radio tuners was discussed last year. The
> > following proposal was accepted:
> >
> > ------- start -----------
> > How to handle tuner ownership if both a video and radio node share the same
> > tuner?
> >
> > Calling S_FREQ, S_TUNER, S_MODULATOR or S_HW_FREQ_SEEK will make the
> > filehandle
> > the owner if possible. EBUSY is returned if someone else owns the tuner and
> > you
> > would need to switch the tuner mode.
> >
> > Ditto for ioctls that expect a valid tuner configuration like QUERYSTD.
> > This is
> > likely to be driver dependent, though. Just opening a device node should not
> > switch ownership.
> >
> > G_FREQUENCY: should just return the last set frequency for radio or TV:
> > requires
> > that that is remembered when switching ownership. This is what happens
> > today, so
> > G_FREQUENCY does not have to switch ownership.
> >
> > G_TUNER: the rxsubchans, signal and afc fields all require ownership of the
> > tuner.
> > So in principle you would want to switch ownership when G_TUNER is called.
> > On the
> > other hand, that would mean that calling v4l2-ctl --all -d /dev/radio0
> > would change
> > tuner ownership to radio for /dev/video0. That's rather unexpected.
> >
> > So just set rxsubchans, signal and afc to 0 if the device node doesn't own
> > the tuner.
> >
> > Closing a device node should not switch ownership. E.g. if nobody has a
> > radio device
> > open, should the tuner switch back to TV mode automatically? The answer is
> > that it
> > shouldn't.
> >
> > How about hybrid tuners? The code to handle tuner ownership should be
> > shared between
> > DVB and V4L2.
> > ----------- end --------------
> >
> > All very nice, but nobody had the chance to actually work on this.
> >
> > But this is how it should work.
>
> Interesting, thanks !
>
> Regards,
> Frank
>
> >
> > Regards,
> >
> > Hans
>
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