[Bug 1172] cannot hear any sound from dialer in GTA02

[bugzilla-daemon at bugzilla.openmoko.org]

http://bugzilla.openmoko.org/cgi-bin/bugzilla/show_bug.cgi?id=1172





------- Additional Comments From andy at openmoko.com  2008-03-14 12:39 -------
There is no shortage of things to go wrong on L/ROUT1 because it is overloaded 
several different ways that already make unsolved troubles.

AMP_3V3 for the amp is connected direct to IO_3V3 which is "always on".  So it 
shouldn't be an issue with amp power otherwise we would see worse behaviours.  
Likewise the codec / mixer is powered quite directly from IO_3V3 itself.

Here are some ways we could possibly make that symptom with that path:

There is an AMP_SHUT net that comes from CPU GPJ01, if this was asserted 
(HIGH) then the amp would be in a low current standby mode.  What it would do 
then if audio arrived at the input is unknown, it could conceivably come out 
at a low level.  So this can be implicated.

Does your version of the kernel still make these ticking noises during boot?  
If so then the DL_GSM (CPU GPIO GPJ6) net can be asserted (low), that can 
create the trouble by driving a logic level on to the ROUT1 (but not LOUT1) 
that would conflict with the amplified audio analogue levels.

Is the headphone socket occupied during this?  If somehow JACK_INSERT (CPU 
GPIO GPF4) and or nHOLD (CPU GPIO GPF7) were driven by the CPU that could 
again conflict with the amplified audio.

Did we confirm there is nothing different with the mixer / codec I2C registers 
when it is happy or sad?

Is there no way we can be doing software scaling at the CPU before sending 
out?



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