[alsa-devel] [PATCH] ALSA: hda - Set TLV_DB_SCALE_MUTE bit for cx5051 vmaster

[Takashi Iwai]

At Sat, 16 Aug 2014 10:34:26 +0800,
Raymond Yau wrote:
> 
> > Conexnat HD-audio driver has a workaround for cx5051 (aka CX20561)
> > chip to add fake mute controls to each amp (commit 3868137e).  This
> > implies the minimum-as-mute TLV bit in TLV for each corresponding
> > control.  Meanwhile we build the virtual master from these, but the
> > TLV bit is missing, even though the slaves have it.
> >
> > This patch simply adds the missing TLV_DB_SCALE_MUTE bit for vmaster,
> > as already done in patch_sigmatel.c.
> >
> > Signed-off-by: Takashi Iwai <tiwai at suse.de>
> > ---
> >  sound/pci/hda/patch_conexant.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/sound/pci/hda/patch_conexant.c
> b/sound/pci/hda/patch_conexant.c
> > index 7627a69ca6d7..6f2fa838b635 100644
> > --- a/sound/pci/hda/patch_conexant.c
> > +++ b/sound/pci/hda/patch_conexant.c
> > @@ -26,6 +26,7 @@
> >  #include <linux/module.h>
> >  #include <sound/core.h>
> >  #include <sound/jack.h>
> > +#include <sound/tlv.h>
> >
> >  #include "hda_codec.h"
> >  #include "hda_local.h"
> > @@ -859,6 +860,11 @@ static int patch_conexant_auto(struct hda_codec
> *codec)
> >         if (err < 0)
> >                 goto error;
> >
> > +       if (codec->vendor_id == 0x14f15051) {
> > +               /* minimum value is actually mute */
> > +               spec->gen.vmaster_tlv[3] |= TLV_DB_SCALE_MUTE;
> > +       }
> > +
> >         codec->patch_ops = cx_auto_patch_ops;
> >
> >         /* Some laptops with Conexant chips show stalls in S3 resume,
> > --
> 
> Does this mean that when there is no hardware mute switch, the driver
> create a fake one using mindB of volume as mute ?

The fake mutes are, yes.

> But this mean that the volume control and mute are not independent anymore,
> just like those pulseaudio volume controls,  volume always change to zero
> after mute and unmute

No, the mute controls are handled individually.
And, this commit itself isn't about the fake mute implementations.
It just give the hint to TLV.


Takashi