Who's playing with scaling_max_freq?

[Stefan Monnier <monnier@iro.umontreal.ca>]

Max scaling_max_freq seems stuck at 1GHz even though it should be able
to go up to 1.83GHz.

    # echo 1833000 >/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq; cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
    1000000
    # cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies 
    1833000 1333000 1000000 
    #

This is on a Thinkpad T60 running Debian stable.  Any idea what might be
causing this?  Or at least, which part of the system might cause
scaling_max_freq to be (re)set to 1GHz right after I force-set it to 1.83GHz?
Would it be some daemon like systemd or rather than kernel?

This Thinkpad T60 is actually used as a desktop: it's parked in a dock
(with the lid is closed) where I have it connected to a keyboard and monitor.


        Stefan