Test for fixed and generic power button

[Paul Menzel]

[Please CC me on replies, as I am not subscribed.]

Dear FWTS folks,


Some boards in coreboot were recently fixed to only advertise one power
button [1].

> mb/google/x86-boards: Get rid of power button device in coreboot
> 
> As per the ACPI specification, there are two types of power button
> devices:
> 1. Fixed hardware power button
> 2. Generic hardware power button
> 
> Fixed hardware power button is added by the OSPM if POWER_BUTTON flag
> is not set in FADT by the BIOS. This device has its programming model
> in PM1x_EVT_BLK. All ACPI compliant OSes are expected to add this
> power button device by default if the power button FADT flag is not
> set.
> 
> On the other hand, generic hardware power button can be used by
> platforms if fixed register space cannot be used for the power button
> device. In order to support this, power button device object with HID
> PNP0C0C is expected to be added to ACPI tables. Additionally,
> POWER_BUTTON flag should be set to indicate the presence of control
> method for power button.
> 
> Chrome EC mainboards implemented the generic hardware power button in
> a broken manner i.e. power button object with HID PNP0C0C is added to
> ACPI however none of the boards set POWER_BUTTON flag in FADT. This
> results in Linux kernel adding both fixed hardware power button as
> well as generic hardware power button to the list of devices present
> on the system. Though this is mostly harmless, it is logically
> incorrect and can confuse any userspace utilities scanning the ACPI
> devices.
> 
> This change gets rid of the generic hardware power button from all
> google mainboards and relies completely on the fixed hardware power
> button.

Looking at proprietary vendor firmware, I noticed they often set up
two power buttons too. This causes no visible problems in my
experience, but it slows down boot a little bit as systemd-logind
goes over these devices for example.

Could you add a test for this problem to FWTS?


Kind regards,

Paul


[1]: https://review.coreboot.org/#/c/coreboot/+/27272/

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