Re: Problems with Centrino frequency modulation

From: Kevin Fenzi
Date: Fri Apr 29 2005 - 19:58:08 EST

>>>>> "Joshua" == Joshua Kwan <joshk@xxxxxxxxxxxxxxx> writes:

Joshua> Hello! I'm running on an IBM Thinkpad T42. APM is
Joshua> working out very nicely in everything except clock modulation,
Joshua> which seems to require ACPI before speedstep-centrino will see
Joshua> it. p4-clockmod is able to wrangle the CPU, but it warns that
Joshua> I should really be using speedstep-centrino as p4-clockmod
Joshua> can't change the CPU voltage.

Joshua> My CPU is family 6 / model 13 / stepping 6 (CPU_DOTHAN_B0 in
Joshua> speedstep-centrino.c.) Is there a way to get
Joshua> speedstep-centrino working without having to use the wretched
Joshua> ACPI (which, among other things, prevents -- or at least makes
Joshua> it a large magnitude harder to -- sleep. If I do echo 3 >
Joshua> /proc/acpi/sleep or echo mem > /sys/power/state, it sleeps
Joshua> correctly, but will wake up with a blank screen or a
Joshua> completely white one. [Observant readers will notice this is
Joshua> exactly what I reported with my last laptop and I'm
Joshua> disappointed to notice that the problem is not restricted to
Joshua> that POS.]) Therefore, I really, really don't want to use
Joshua> ACPI.

Not that you want to hear it, but I have a T42p (that I just got a few
weeks ago) and it can do S3 suspend/resume just fine.

There are 3 things you need to do:

boot with: "acpi_sleep=s3_bios"

rmmod all the usb modules before suspending.

do not use the binary only ati drivers.

I use the hibernate script from the suspend2 project:
set to do S3 instead of suspend2, which also unloads blacklisted
modules (Including the usb ones) and re-loads them on resume.

You might try that if you get a chance. ACPI has come a long way...

Joshua> Thanks.
Joshua> -- Joshua Kwan


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