Fixing Sound/Suspend-Resume on IBM T23 for Gentoo

ALSA does work, as I mentioned here, but it seems to have problems across a suspend-resume, i.e. it doesn't work post-resume.

Previously used patches don't seem to apply to newer Alsa modules.

Gentoo installs apmd_proxy in /etc/apm, with suspend.d and resume.d directories for handling special suspend/resume operations. Even better, event.d handles both.

So, based on some searching around, I ended up adding apmd to the list of services to start (rc-update add apmd default), and added the following script to get alsa to behave on resume:

/etc/apm/event.d/alsa:

#!/bin/sh

case "$1" in
resume)
    /usr/sbin/alsactl power off
    /usr/sbin/alsactl power on
    ;;
suspend|standby)
    ;;
esac

Found this lovely snippet that answers why apm -s works better than Fn-F4 [emphasis added]:

The APM BIOS rejects suspend (or hibernate) requests under certain conditions: e.g., on my TP600, when my Xircom Ethernet/modem card is inserted and the machine is on AC power. If I do apm —suspend then the kernel apm driver hears about the request first and tells apmd which runs apmd_proxy which runs the scripts in /etc/apm/event.d which do things like eject the PCMCIA cards; only then does the apm driver pass the request on to the BIOS. (I think.) If I do tpctl —suspend on the other hand, the BIOS hears about the request first and, if the PCMCIA card is still inserted, it rejects the request with a couple of beeps (high—-low). apm —suspend is therefore to be preferred to tpctl —suspend.
Unfortunately, there is no alternative to tpctl —hibernate : the apm program and the kernel apm driver don't know how to ask for hibernation. Solution: write a little script that does cardctl eject ; tpctl —hib. Fn-F4 does the same as tpctl —suspend and Fn-F12 does the same as tpctl —hibernate.

The mention of the BIOS rejecting the suspend request when a PCMCIA card is inserted is exactly what I was seeing – I'm using my wireless card right now.

So after all that, I learned that I should suspend using apm -s and not with the thinkpad buttons if I have a pcmcia card active. With no PCMCIA card, the suspend request will be handled correctly by APM and apmd, and everything should be happy.

References:

Why doesn't my Thinkpad hibernate? | Linux-ThinkPad FAQ

Various records of Linux Installation attempts:

Older Alsa drivers:

Information for Linux on IBM Laptops

APM / Other tools

Everywhere I looked, things would reference debian's /etc/apm/event.d/alsa script. Thing is, I don't run debian, and I'll be damned if I could find the contents of the script anywhere.

For future reference, I've attached the source here.