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cpufreq: userspace: set CPUFREQ_GOV_STRICT_TARGET flag

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When the userspace governor is used, the user intends to set a fixed CPU
frequency for a policy, for whatever reason. The CPUFREQ_GOV_STRICT_TARGET
flag is the required behaviour. Without this flag, the intel_pstate driver,
with HWP enabled, will set HWP_MIN_PERF to the target frequency and
HWP_MAX_PERF to the policy maximum, when configuring the HWP_REQUEST MSR.

This lets the hardware choose any frequency between the target frequency
and the policy maximum, which is not the intended behaviour. To fix this,
`cat scaling_setspeed > scaling_max_freq` had to be done. With this patch,
that is no longer necessary. Setting scaling_setspeed is sufficient, as
expected.

Signed-off-by: Shashank Balaji <shashank.mahadasyam@sony.com>
Link: https://patch.msgid.link/20250527-userspace-governor-doc-v2-1-0e22c69920f2@sony.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Shashank Balaji 2025-05-27 21:59:09 +09:00 committed by Rafael J. Wysocki
parent c83a92df2f
commit 2e1185c9d7
1 changed files with 1 additions and 0 deletions
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drivers/cpufreq/cpufreq_userspace.c
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@ -134,6 +134,7 @@ static struct cpufreq_governor cpufreq_gov_userspace = {
.store_setspeed = cpufreq_set,
.show_setspeed = show_speed,
.owner = THIS_MODULE,
.flags = CPUFREQ_GOV_STRICT_TARGET,
};
MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>, "