[ltp] Thinkpad R40 2722: various CPUFREQ troubles

d.lj linux-thinkpad@linux-thinkpad.org
Thu, 11 Dec 2003 15:01:36 +0100 (CET)

you can try disabling CONFIG_X86_UP_APIC (apic on uniprocessors) or
append="noapic" to your kernel arguments if that helps for the timing

i have apm and enhanced speedstep which works just fine with cpudynd on
R40 2722 with 2.6.0-test9.


[Sebastian Kapfer]->[[ltp] Thinkpad R40 2722: various CPUFREQ...

 |Hello Thinkpad users,
 |My Thinkpad R40 (2722-GDG) works quite well under Linux, except for a
 |few obstacles. It would be nice if someone could shed a bit of light on
 |the issue. I have found a mail with a single question on this list, but
 |without a real solution. :-(
 |* I Can't clock the machine at 1500 MHz when disconnected from external
 |power. I know IBM wants to conserve battery power here. BUT I DON'T
 |CARE. A useless (slow) system is worse than one running two hours less.
 |Does this depend on BIOS settings? I think I tried everything possible,
 |but never got past 600 MHz.
 |* The system time runs slow. Order of magnitude is about 5 minutes slow
 |per hour of operation. This doesn't seem to occur when it is turned off.
 |I have to ntpdate several times a day. :-(  CPU frequency doesn't seem
 |to have any influence. Time is lost at about the same speed no matter if
 |1500 or 150 MHz. Google says ACPI will fix this (and it does), but with
 |ACPI the battery status doesn't work any more.
 |* Strange message in the syslog (appears once, some minutes after
 || Losing too many ticks!
 || TSC cannot be used as a timesource. (Are you running with SpeedStep?)
 || Falling back to a sane timesource.
 |The answer to that question is probably "yes". The fallback timesource
 |obviously isn't more sane either, because it's still wrong :-(
 |After hours of googling, I found out that there's a kernel parameter
 |which controls the default timesource. Available options are "pit",
 |"tsc" and "cyclone".
 |cyclone isn't accepted by the kernel at all; tsc is the default anyway,
 |and when booted with clock=pit, CPUFREQ fails to detect a CPU. So I'm
 |not sure what to do to get rid of this message.
 |Summary of the system configuration:
 |Pentium M CPU, Linux 2.6-test9 kernel with the CPUFREQ stuff, APM mode,
 |acpi=off (you know, the battery).
 |BIOS settings: CPU frequency is set to "fixed max". (But still the CPU
 |runs at 600 instead of 1500.)
 |Enabling or disabling SpeedStep in the BIOS doesn't make any difference
 |whatsoever. CPUFREQ happily changes frequency in both modes, the system
 |time is slow in both.
 |Please help!

x          D          v          .          o          r          g
GPG-key at http://xdv.org/~jdl/jdl.pub.asc