[Bug 218305] Ryzen 7 7840HS gets stuck at 544MHz frequency after resuming after unplugging the power cord during sleep

[bugzilla-daemon@kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=218305

gunnar.kistner@gmail.com changed:

           What    |Removed                     |Added
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                 CC|                            |gunnar.kistner@gmail.com

--- Comment #158 from gunnar.kistner@gmail.com ---
I can reproduce what appears to be the same issue on a different HP AMD laptop.

Hardware and software:

* HP ZBook Power 16 inch G11 A Mobile Workstation PC
* Product number: 9A818AV
* AMD Ryzen 9 PRO 8945HS with Radeon 780M Graphics
* BIOS: W85 Ver. 01.10.05
* Embedded-controller firmware: 8.82
* Ubuntu 24.04.4 LTS
* Current kernel: Ubuntu 7.0.0-28-generic
* Also observed with Ubuntu 6.17.0-35-generic
* amd-pstate active / amd-pstate-epp

The issue occurs when the AC adapter state changes while the laptop is fully
suspended.

Confirmed reproduction:

1. Suspend while connected to AC.
2. Wait until the laptop has fully entered suspend.
3. Disconnect AC while it is suspended.
4. Resume on battery.
5. All 16 logical CPUs may remain fixed at approximately 544 MHz, even under
full CPU load.

The reverse sequence has also been observed:

1. Suspend while running on battery.
2. Connect AC while fully suspended.
3. Resume while connected to AC.
4. The CPUs may again remain fixed at approximately 544 MHz.

Changing powerprofilesctl between balanced and performance does not help.

When affected, Linux still reports:

* scaling_max_freq: approximately 5.263 GHz
* cpuinfo_max_freq: approximately 5.263 GHz
* CPU boost: enabled
* amd-pstate status: active

Briefly changing the AC adapter state again after resume immediately restores
normal frequency scaling. Under the same 16-thread load, the CPU then reaches
approximately 4.39 GHz.

Ubuntu downstream report:

Launchpad Bug #2162127

I have attached a combined log containing the CPU state before and after the
recovery AC event, the cpufreq limits, and the relevant udev power-supply
events.

The complete before/after evidence is attached to Ubuntu Launchpad Bug
#2162127.

Key results from the attachment:

* Before the recovery AC event, all 16 logical CPUs remain at approximately 544
MHz under full load.
* After briefly changing the AC adapter state, the same test reaches
approximately 4.39 GHz.
* `scaling_max_freq` and `cpuinfo_max_freq` remain approximately 5.263 GHz in
both states.
* AMD P-State remains active, CPU boost remains enabled, and the power and
platform profiles remain balanced.
* The recovery event is detected normally as `POWER_SUPPLY_ONLINE=1`; after
disconnecting AC again, the system returns to `POWER_SUPPLY_ONLINE=0` and
battery discharging, while normal CPU performance remains restored.

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