Sound Issues Thinkpad 600X - ALSA playback choppy, OSS crashes

This bug is was also reported for Hoary, however it was closed and never fixed.
https://bugzilla.ubuntu.com/show_bug.cgi?id=8477

This bug was previously reported as a blank screen after login, although the
problem appears to be more than that.

Two immediately noticable problems were that the drums noise that normally plays
when GDM is ready, was very stretched and choppy - played slowly and in bursts.
Then after logging in, GNOME hung at a blank desktop (where the startup sound
would normally play).

I came across the original bug report when looking for reasons why GNOME hung on
startup; after solving that problem (disabling the sound server on startup) it
became apparent that more than just the sound was broken.

I could not get the PCMCIA network card I had to work - Linux detected it, I
could configure it and the lights flashed promisingly, but I could not get any
data transfer. Adding the irqpoll as suggested in the original bug report not
only fixed the network card, it also fixed the sound playing at GDM startup.

This was not the end of the problems; audio playback via ALSA sounded very
choppy, and at times was indistinguishable from the actual source (i.e. if you
were playing a CD). Switching the default audio sink in the GStreamer properties
to OSS fixed the choppy sound, however it caused huge system instability during
audio playback - the computer would randomly crash completely (cursor locks up,
keyboard locks up, no response from Ctl alt del or from ACPI events (like
pressing the powerbutton). Using Enlightenment Sound Daemon as the audio sync
seemed to be slightly more stable, but still crashed.

I have looked around the internet; and from what I could gather, the problem
appears to be an IRQ problem, however bar the irqpoll parameter, none of the
other options suggested on the Ubuntu Wiki (can't recall the page) made any affect.

I tried loading the kernel module(snd-cs46xx) with the thinkpad=1 module (hack
to workaround the CLKRUN problem with the Thinkpad's power management) and I
also tried disabling the power management on PCI bus and adding more IRQs for
PCI using the DOS based PS2.exe program from the dos utilities disk, but that
doesn't seem to help either.

It may also be worth noting that general sounds in GNOME seem to work fine (like
the ding noise that GAIM makes or the menu click noises); but audio playback
seems to have problems.

A bit of background about this computer:
Running Ubuntu Breezy (5.10)
IBM Thinkpad 600X
Mobile Pentium III 500MHz
256MB RAM
Cirrus Logic CS4614/22/24 sound card chipset (uses ALSA driver snd-cs46xx and
oss driver cs46xx)
Running using an incorrect power supply (lower than recommended current rating;
I haven't butchered together supply closer to the actual current rating. I
guessed that it might be caused by not enough current being supplied to the
CPU/motherboard, (iPod, PCMCIA network card + CDROM drive on top of the rest of
the system) but the same problem occured when running off batteries.)