[alsa-devel] call/normal switch was Re: omap4-droid4: voice call support was

[Tony Lindgren]

* Dan Williams <dcbw at redhat.com> [180402 15:51]:
> On Sun, 2018-04-01 at 10:30 -0700, Tony Lindgren wrote:
> > * Tony Lindgren <tony at atomide.com> [180401 15:38]:
> > Found it! Here's what I need to do over n_gsm:
> > 
> > ngsm 1 "AT+CFUN=1"
> > ngsm 1 "AT+CFUN?"
> > ngsm 2 "AT+EACC=3,0"    # enable mic
> > ngsm 2 "AT+CLVL=4"      # set speaker volume
> > ngsm 2 "AT+CMUT=0"      # unmute mic
> 
> I tried to look through the QMI dumps we have in libqmi from 2013
> (latest Qualcomm posted) and couldn't find anything to do with mic
> control, speaker volume, or anything like that.
> 
> If the modem supports the AT service (which I think it does?  Not
> looking at the libqmi dumps right now) then it could potentially tunnel
> these AT commands through QMI too.
> 
> Perhaps Qualcomm added something to the Voice service after 2013, or
> perhaps there are other services that might control speaker/mic that we
> don't have public dumps for yet though.

OK thanks for checking. So probably only n_gsm channel 1 is for normal
Qualcomm at commands, and then channel 2 and others are commands
implemented by Motorola on the mdm6600.

I guess we'd have to add support for reading and writing to
/dev/gsmtty2 at least as it looks like these cannot be accessed
via /dev/ttyUSB4. Or at least I have not figured out any other
way to access them.

Regards,

Tony