[ltp] ACPI on a T30

[Ramon Casellas]

On Mon, 8 Sep 2003, Herbert Szumovski wrote:

> Hi,
> is there somebody who got ACPI working on a Thinkpad ?


I do (more or less).


What I have gathered, as I remember:

* Some thinkpads have a wrong ECDT table. There exists a C program
(verify_ecdt.c)  that ckecks this. It is possible to overwrite it by
patching file osl.c

* For some people, there is a specific kernel version and acpi patch (I
think that it was 2.421-ac1 but don't quote me on this) that more or less
works.

* Some versions (IIRC 2.4.18-2.4.21prex :?) also suffered from
things like CPU going to 100%, keventd taking all CPU, system hangs, etc.
It is a kernel bug (diagnostic: close lid/open lid or press Fn+Stg, dang
sslooow)



Most recent thinkpads (I can think of X31, A31, R40, T30) are "out of the
box" unable to use ACPI do to several kernel acpi system bugs:

* Make sure to update to the latest bios, available from ibm.com, you may
upgrade by using a floppy disk or by booting into windows.

* If you get lots of AE_TIME and EC messages, it is probably that the ACPI
system is unable to find your embedded controller. There is a bug report
on bugme.osdl that summarizes it. There are some patches that are specific
to the thinspads.  :
http://bugme.osdl.org/show_bug.cgi?id=1038 and comments in:

 http://erkki.tty0.org/thinkpad/thinkpad-acpi.html

IIRC these patches are not yet in the main ACPI patches (status Assigned)

The "one big patch" in the erkki web patch applies cleanly to
2.6.0-test3... test4-mm6.

Patches are also available for 2.4.22/23pre kernels.

* You may also want to override your DSDT table. see the acpi web page for
details (link below).





This "patch set" is what I use to get an acpi sbsystem that "is ok"
(although there are some glitches and I'm unable to
suspend/resume/hybernate. I use 2.6.0-test4-mm6 on gentoo)

You may also want to take a look at
acpi.sf.net and
projects.sf.net/projects/acpi
for more info (cf. mailing lists)


Finally, make sure to check
http://www.linux-laptop.net/ibm.html
for your specific model and see Power Management/ACPI sections on the
installation reports (if any).

Regards,
Ramon


> I use a 2.4.20 kernel (self compiled GenToo 1.4), which
> works fantastic, with the exception of ACPI, though it's
> compiled in.  I'm thinking of stepping back to APM, but
> wanted to know if there is a positive experience out there.
>
> Thanks, Herbert
>
> --
> The linux-thinkpad mailing list home page is at:
> http://mailman.linux-thinkpad.org/mailman/listinfo/linux-thinkpad
>

// --------------------------------------------------------
// Ramon Casellas 		GET/ENST/INFRES/RHD/C206
// casellas@infres.enst.fr