[alsa-devel] [PATCH] [RFC 8/13] Intel SST sound card driver
tiwai at suse.de
Tue Jul 7 09:11:26 CEST 2009
At Tue, 7 Jul 2009 12:34:16 +0530,
Harsha, Priya wrote:
> >-----Original Message-----
> >From: Takashi Iwai [mailto:tiwai at suse.de]
> >Sent: Tuesday, July 07, 2009 12:19 PM
> >To: Harsha, Priya
> >Cc: Koul, Vinod; alsa-devel at alsa-project.org
> >Subject: Re: [alsa-devel] [PATCH] [RFC 8/13] Intel SST sound card driver
> >At Tue, 7 Jul 2009 11:50:46 +0530,
> >Harsha, Priya wrote:
> >> >
> >> >> + .access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
> >> >> + .info = snd_intelmad_line_volume_info,
> >> >> + .get = snd_intelmad_volume_get,
> >> >> + .put = snd_intelmad_volume_set,
> >> >
> >> >Can it have the dB information via TLV?
> >> No. It actually differs across the 3 sound cards supported and it's
> >> not a direct TLV that can be used.
> >Then you'd set a static TLV entry after creating the ctl element
> >instance, or return a TLV entry dynamically via the tlv callback.
> Sorry I misunderstood. The value that is passed in min and max is in
> For min and max values, it's a static dB value that I return. But
> when the volume adjustments need to be done, based on the value
> given by ALSA, I set the sound card registers to reflect that dB
The value to be set is always raw. That is, alsa-lib computes the
raw value from the given dB value based on the TLV information (dB
min/max), supposing the volume scale is logarithmic.
Isn't it the case for you?
> When volume is queried for, I read the specific sound card
> register and return the dB value to ALSA.
> Will this implementation be ok?
More information about the Alsa-devel