Re: APM realy sucks on 2.6.x

From: Sebastian Kloska
Date: Mon Jun 07 2004 - 09:29:47 EST


Hi again

Thanks for the hint on device_suspend (realy !! gives me a starting point
for debugging.


Pavel Machek wrote:
Hi!


I'm really willing to help the APM developers to track down this bug
but don't have a clue how to debug this kind stuff.


What APM developers? There are none as far as I know.


Hmmm ... So once again the Tooth Fairy and Santa Claus :-) ?

At least a

grep '<.*@' /usr/src/linux-2.6.6/arch/i386/kernel/apm.c | sed 's/.*<//' | sed 's/>.*//'

gives me:

<snip>
Ulrich.Windl@xxxxxxxxxxxxxxxxxxxx

...

chen@xxxxxxxxxxxxxx
</snip>

This is pretty much for no one. And I guess you knew since you're on
the list yourself. But I think you're right when meaning
that there is not much of active maintenance anymore. Which at
least I find a little bit discouraging when looking of the state
of the ACPI support.


Yes, that's pretty much what I meant. ACPI has ~5 people actively
working on it, some of them probably full-time. That's a lot of
manpower, compared to APM.


This becomes a little bit scary. Someone else on this list already
mentioned that there is a strong movement towards everything which
is at least a desktop/server machine. And on the other hand there are
these embedded systems which seem to be attractive for linux to.

ACPI seems to be nifty for such things like hardware monitoring and
stuff. That makes it interesting for servers etc...

Everything in the middle (aka laptops) seems to slowly drop out of the
loop. PCMCIA seems to be another ugly example. Anyway ... I'm not frightened
by this manpower. Just want to have my laptop running 2.6.x and suspending
to RAM. I'll do my very best and report back if there are any significant
findings.....


And ACPI is in pretty good state, btw, unless you want
suspend-to-RAM. Unfortunately you want suspend-to-RAM.


Try removing calls to device_* in apm.c. Better yet become APM
developer.

It seems like I'm on my way to do so (still reluctantly). As I stated
in my previous mails I'm not born as a hardware/BIOS hacker (more the
application C++/Java stuff) but I'm willing to learn. When I'm
grown up I definitely want to be linux kernel hacker :-) ...

Currently I ripped down the 2.6.6 kernel to almost nothing
and add one module after the other checking for proper
suspend/resume behavior....

The most suspicious candidates on my list are currently the
USB-UHCI driver and the ALSA sound system, which is my #1 candidate
since it has not been an integral part of the 2.4.x (x<=20) kernels.


So if anybody out there could give me guidance on how the apm code
might interact with the ALSA sound system it would be highly
appreciated....


device_suspend() will propagate all the way to alsa.
Pavel


--
**********************************
Dr. Sebastian Kloska
Head of Bioinformatics
Scienion AG
Volmerstr. 7a
12489 Berlin
phone: +49-(30)-6392-1708
fax: +49-(30)-6392-1701
http://www.scienion.de
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