platform_profile: power-saver lost on Panther Lake when SoC Power Slider and dell-pc are both bound (low-power vs quiet)

platform_profile: power-saver lost on Panther Lake when SoC Power Slider and dell-pc are both bound (low-power vs quiet)

[verazimmerman1987]

Hi,

On a Dell XPS 14 (2026, Panther Lake, Core Ultra X7 358H) two platform
profile handlers are registered, and their choices have no common
low-power option, so the legacy /sys/firmware/acpi/platform_profile
interface exposes only "balanced performance". As a result
power-profiles-daemon cannot select a low-power firmware mode in
power-saver.

Handlers:

  platform-profile-0  name: SoC Power Slider
                      choices: low-power balanced performance
  platform-profile-1  name: dell-pc
                      choices: cool quiet balanced performance

  /sys/firmware/acpi/platform_profile_choices: balanced performance

Effect: power-saver in power-profiles-daemon leaves both handlers at
"balanced". The Dell firmware stays in its "optimized" mode, so
thermald --adaptive keeps applying the optimized DTT table (PL1
19-25 W) instead of the quiet/cool tables (PL1 15-19 W, lower skin
temperature targets). Setting the handlers individually
(dell-pc=quiet, SoC slider=low-power) works and thermald picks the
"quiet" target, but the legacy file then reports "custom" and
power-profiles-daemon falls back to "balanced", so there is no
consistent way to use it.

This looks like the same class of problem as amd-pmf + asus-wmi,
which was solved by adding "quiet" as a hidden choice in amd-pmf
(commit 44e94fece517, "platform/x86/amd: pmf: Add 'quiet' to hidden
choices"). Would a similar hidden "quiet" (and perhaps "cool") choice
for the Intel SoC Power Slider, mapped to its low-power setting, be
acceptable? I'm happy to test patches.

System:
  Kernel: 7.2.9-arch1-1
  DMI: Dell Inc. XPS 14 DA14260, BIOS 1.11.0
  power-profiles-daemon: 0.30-1
  thermald: 2:2.5.13-1

Thanks,
Vera

Re: platform_profile: power-saver lost on Panther Lake when SoC Power Slider and dell-pc are both bound (low-power vs quiet)

[Lyndon Sanche]

Hello, thank you for reporting this.

To me there are a number of ways we could handle this.

On Fri Oct 16, 2026 at 1:10 PM EDT, verazimmerman1987 wrote:
> This looks like the same class of problem as amd-pmf + asus-wmi,
> which was solved by adding "quiet" as a hidden choice in amd-pmf
> (commit 44e94fece517, "platform/x86/amd: pmf: Add 'quiet' to hidden
> choices"). Would a similar hidden "quiet" (and perhaps "cool") choice
> for the Intel SoC Power Slider, mapped to its low-power setting, be
> acceptable? I'm happy to test patches.

This certainly would fix the immediate issue: platform_profile providing
consistent choices across handlers to allow selecting a range of
profiles exposed by the system. I feel like there is a better way to
handle this besides adding hidden profiles.

What if platform_profile itself was changed to separate the user/system
choice: the "desired" profile, from the "actual" profile(s)? In this
scenario, different drivers expose different possible profiles, the
system tries to apply the closest possible profile per-driver to the
user's choice. The possible profiles would have an index to indicate
where on a linear scale it lays. If I request quiet (2), but the Intel
SoC slider only implements power-saver (3), the system chooses 3 for
that driver.

I am only thinking out loud and would find comments on this to be
useful. I realize the behaviour of some profiles do not exactly fall on
a linear scale so this would need consideration as well.

Thanks,

Lyndon