Tim E. Real wrote: > On July 27, 2010 01:00:31 am you wrote: > > > Yikes! It's all coming back to me now, this can of worms. > > > In my case the Delta101LT card has the AK4524 ADCs. > > > The dB step of the IPGA stage is constant at 0.5dB, but the > > > dB step of the DATT stage is not - anywhere from 6dB to 0.28dB ! > > > And remember the IPGA and DATT controls were combined, complicating > > > things. Meanwhile, other AK chips' DATT stages are constant step.
The driver uses a volume lookup table to pretend that the mixer values have constant 0.5 dB steps. This should be changed. > > So does this mean 'alsamixer' has a bug for those card models with > > combined IPGA? Which would that be? > > > > Note the code in 'alsamixer' which prints out dB-values -- is this > > correct or not? If there is a bug, it is in the TLV tables in the driver. > Apparently there is a more advanced TLV based dB conversion. > snd_tlv_convert_to_dB() The snd_mixer_selem_get_*_dB functions just get the TLV table and then call snd_tlv_convert_to_dB internally. Regards, Clemens _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/listinfo/linux-audio-dev
