Background noise during conversation

[allen_lin@…]

When talking through Neo FreeRunner?, there is no background noise at Neo
FreeRunner? side, but some noise at another phone side.

uImage-2.6.24+svnr4301-r4251-r5-om-gta02.bin
Openmoko-openmoko-freerunner-image-glibc-ipk-P1-Snapshot-20080403-om-gta02.rootfs.jffs2

[werner@…]

Following up on the GTA02 phone conference:
The ALSA-related item is "Amp Stat". Muting it kills the GSM download
noise, but the mechanism if independent from
/sys/devices/platform/neo1973-pm-gsm.0/download

Thus, the "time bomb" only ticks if
Amp_Stat != Muted && download == enabled

where the value of "enabled" is 1 without Holger's patch, and 0 without it.

Since u-boot already sets this GPIO to the correct value, the easiest
solution is if Linux does not change it. In my somewhat dated rootfs, I
found the following places where it does change it:

/etc/init.d/gsmd:

[ -n "$GSM_DL" ] && ( echo "1" >$GSM_DL; sleep 1 )

So just removing this line should solve the problem. It may also be worth
checking if gsmd or any wrapper or such tries to change "GSM_DL" as well.

Oh, and svn.internal.openmoko.org/trunk/production_testing/gta02-dm2/src/dm2.c
has a few writes to /sys/bus/platform/devices/neo1973-pm-gsm.0/download,
so this probably needs some updating as well.

[erin_yueh@…]

John updated this gsmd script and uploaded it to OE. Thanks! Werner! :)

[hiciu]

What about this: ​http://lists.openmoko.org/pipermail/community/2008-August/028495.html ?

[john_lee]

hardware issue. refer to ​http://lists.openmoko.org/pipermail/hardware/2008-August/000415.html