Problems with Centrino frequency modulation

From: Joshua Kwan
Date: Fri Apr 29 2005 - 19:00:31 EST


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

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

Any suggestions?


Joshua Kwan

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