[ltp] sound on Thinpad 600 with Sarge (Yet again...)

[linux-thinkpad@linux-thinkpad.org]

> From: Sriram Karra <skarra@gmail.com>
> 
> I have a Thinkpad 600 (2645-48U) that I have just started using after
> a really long time.  The sound was working even ~4 years ago with
> Debian Potato.  But Sarge is having issues.  I did go through the
> archives and tried out different things.  Most specifically disable
> BIOS Quick Boot.  After doing that I did start getting Beeps from the
> speakers but xmms and stuff still refuse to work.
>....
> And oh, btw.  I also tried ugprading to 2.6.11 kernel from sid.  That
> did not work either.
> 
> Thanks,
> -Sriram.

THAT, btw, looks like your main problem.
I bet you first tried to run a 2.6 kernel and THEN you had no more sound!
Nobody seems interested, so there's little to no chance that this will
ever be fixed. I couldn't even get people (at kernel.org and gentoo)
interested to just only stick a big warning in the sources.

I'm glad to see that there still are a few TP600 users around.
So I'll try a last big warning:

  DO NOT TRY TO RUN WHATEVER KERNEL 2.6 IN YOUR TP600, EVER!

Always check your boot tools for kernel versions in another machine first.

Every 2.6 kernel will crash sooner or later, most often even before reaching
the prompt. (Except for a kernel with hotplugging disabled. That kernel will
run, but without hotplugging there's hardly anything useful to do with your
laptop.)

ANY attempt to start a 2.6 kernel will disable the sound chip permanently.
The good news is that the damage appears not to be irreversible.
However, all methods to get it back to life are all quite tedious and not
suitable for Joe Average. (The question remains if there is any Joe Average
using a TP600?)

Anyway, the easiest and less damaging way to get your sound back is:
- Shut down your TP600 and unplug the power cable.
- Take out the battery pack (to ensure that the CMOS RAM can get empty).
- Open/remove the lid that covers the RAM modules and CMOS battery.
- Unplug the CMOS battery. (That tiny connector in the corner).
- Wait a moment. (A few minutes suffices).
- Put everything back together again.

Now you'll have sound back (if you use cs4232.o).

There might even be a cleaner method that I haven't tried yet (AFAIR).
I would have tried it in my DOS days, but under linux I don't have the
tools at hand.  If you change even just one byte in CMOS, so that it makes
the checksum invalid, then the BIOS might think that the battery failed.
A subsequent reboot will reset all fields to a sane value, just as
when you really remove the battery.
Not all CMOS bytes are checksum protected. You'd better check Ralf Browns
Interrupt List, or other sources. Let's hope that the TP600 is sufficiently
IBM compatible :-).

Is there anyone that successfully runs a 2.6 kernel on a TP600[e] ?

Regards,
Wim Osterholt.