At Tue, 7 Jul 2009 12:46:38 +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 > >> dB. > >> 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 > >> value. > > > >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? > Yes. I set the raw min and max values in db. And alsa-lib computes > the volume value to be set (which is in between the min and max) and > provides the same to the driver. The driver sets the corresponding > sound card registers to reflect the same. In our case, the scale is > not logarithmic in couple of sound cards and the vendor abstraction > file would need to take care of the same to set the registers > correctly. Then it can't be exported as the existing TLV. The currently defined TLV types are logarithmic, linear, and combinations. I think it's better to fix the driver side to be logarithmic. Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
