[ltp] What's cutting my CPU speed in half? / (FC6 upgrade bug)

[Mendel Cooper]

On Thu, 16 Nov 2006, Daniel Maier wrote:

> >   Some thinkpads, when booted w/o AC power plugged in, boot at a
> > reduced speed.
> >
> >   You can't switch it back up to full speed w/o the cpufreq drivers &
> > apps - unless you want to reboot with AC plugged in.
> This is a BIOS setting which can be set to customized for both,
> battery and AC.
>
> Have a look at:
> /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor and
> scaling_max_freq.

I was going to make this the topic of a separate post, but since it has
been brought up . . .

There is a bug in Fedora Core 6 that screws up the /sys directory
so that /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
doesn't exist and you can't create it. So, /usr/sbin/cpuspeed and /usr/sbin
cpufreq-selector abort with an error and you can't adjust the cpu speed.
Note, however, that this bug exists *only* for an upgrade from
FC5 --> FC6. If you're doing a fresh, from scratch install then cpuspeed seems
to work all right.

Yeah, I know, I know, a fresh install is recommended . . . but the FC4
--> FC5 upgrade worked all right, and an upgrade saves mucho time since
you don't have to do nearly as much tweaking.