[alsa-devel] [PATCH] ALSA: jack: create jack kcontrols for every jack input device

[Takashi Iwai]

At Thu, 19 Mar 2015 11:51:23 +0100,
Takashi Iwai wrote:
> 
> At Thu, 19 Mar 2015 16:40:18 +0800,
> Jie Yang wrote:
> > 
> > From: Liam Girdwood <liam.r.girdwood at linux.intel.com>
> > 
> > Currently the ALSA jack core registers only input devices for each jack
> > registered. These jack input devices are not readable by userspace devices
> > that run as non root.
> > 
> > This patch adds support for additionally registering jack kcontrol devices
> > for every input jack registered. This allows non root userspace to read
> > jack status.
> > 
> > Signed-off-by: Liam Girdwood <liam.r.girdwood at linux.intel.com>
> > Modified-by: Jie Yang <yang.jie at intel.com>
> > Signed-off-by: Jie Yang <yang.jie at intel.com>
> > Reveiwed-by: Mark Brown <broonie at kernel.org>
> > ---
> >  include/sound/control.h |  2 ++
> >  include/sound/jack.h    |  2 ++
> >  sound/core/jack.c       | 89 +++++++++++++++++++++++++++++++++++++++++++++++--
> >  3 files changed, 91 insertions(+), 2 deletions(-)
> >  mode change 100644 => 100755 sound/core/jack.c
> > 
> > diff --git a/include/sound/control.h b/include/sound/control.h
> > index 75f3054..023b70a 100644
> > --- a/include/sound/control.h
> > +++ b/include/sound/control.h
> > @@ -66,6 +66,7 @@ struct snd_kcontrol_volatile {
> >  
> >  struct snd_kcontrol {
> >  	struct list_head list;		/* list of controls */
> > +	struct list_head jack_list;		/* list of controls belong to the same jack*/
> >  	struct snd_ctl_elem_id id;
> >  	unsigned int count;		/* count of same elements */
> >  	snd_kcontrol_info_t *info;
> > @@ -75,6 +76,7 @@ struct snd_kcontrol {
> >  		snd_kcontrol_tlv_rw_t *c;
> >  		const unsigned int *p;
> >  	} tlv;
> > +	unsigned int jack_bit_idx;	/*the corresponding jack type bit index */
> >  	unsigned long private_value;
> >  	void *private_data;
> >  	void (*private_free)(struct snd_kcontrol *kcontrol);
> 
> NAK for these additions.  There must be a way to implement without
> such *generic* additions in kcontrol.

IOW, you can allocate its own record in kctl->private_data.  Currently
hda_jack.c is the only user of snd_kctl_jack_*().  So, if we remove
these callers, we can assign kctl->private_data for jack's own
purpose.  There you'll allocate own record for keeping tracking the
list and bitmap, etc.


Takashi