cpufreq/thermal regression in 6.10

From: Johan Hovold
Date: Sun Jun 09 2024 - 03:53:32 EST


Hi,

Steev reported to me off-list that the CPU frequency of the big cores on
the Lenovo ThinkPad X13s sometimes appears to get stuck at a low
frequency with 6.10-rc2.

I just confirmed that once the cores are fully throttled (using the
stepwise thermal governor) due to the skin temperature reaching the
first trip point, scaling_max_freq gets stuck at the next OPP:

cpu4/cpufreq/scaling_max_freq:940800
cpu5/cpufreq/scaling_max_freq:940800
cpu6/cpufreq/scaling_max_freq:940800
cpu7/cpufreq/scaling_max_freq:940800

when the temperature drops again.

This obviously leads to a massive performance drop and could possibly
also be related to reports like this one:

https://lore.kernel.org/all/CAHk-=wjwFGQZcDinK=BkEaA8FSyVg5NaUe0BobxowxeZ5PvetA@xxxxxxxxxxxxxx/

I assume the regression may have been introduced by all the thermal work
that went into 6.10-rc1, but I don't have time to try to track this down
myself right now (and will be away from keyboard most of next week).

I've confirmed that 6.9 works as expected.

Johan


#regzbot introduced: v6.9..v6.10-rc2