Re: [RFC PATCH 0/3] platform: lenovo: architecture independent home for the Lenovo WMI drivers

[Hans de Goede <hansg@kernel.org>]

p.s.

On 15-Nov-26 21:10, Hans de Goede wrote:
> On 15-Nov-26 16:33, Hans de Goede wrote:
> 
> <snip>
> 
>>>   b. Should the Fn key event handling stay a separate small driver, or
>>>      be factored out of ideapad-laptop so x86 and arm64 share one path?
>>>      ideapad-laptop handles the event only when its VPC platform driver
>>>      is bound, and the arm64 machines expose none of the VPC interface
>>>      it is built on (no _CFG, VPCR/VPCW, DYTC or HALS/SALS), so making
>>>      it the single driver means gating most of its probe. Two smaller
>>>      options: lift ideapad-laptop's own Fn key wmi_driver and keymap
>>>      into this file and let ideapad-laptop register for the events it
>>>      still wants (Fn lock LED, DYTC cycle), or the hid-asus/asus-wmi
>>>      shape where a companion WMI module exports the event to a
>>>      subsystem driver. The keymap in patch 2 duplicates entries of
>>>      ideapad-laptop's table on purpose until that is decided.
>>
>> IIRC the ideapad-laptop driver is a bit of a mess atm, so factoring
>> a common handling for the the Fn key events out of this and sharing
>> that sounds like a nice cleanup.
>>
>> I see that patch 2/3 uses the new wmi-driver/-bus infra which is
>> nice and clean.
>>
>> So maybe just keep your existing stand-alone driver for both x86_64 +
>> arm64 and drop the WMI event handling from ideapad-laptop.
>>
>> I guess this may hit some problems where WMI event handlig is used
>> in ideapad-laptops integrating with some VPC functionality.
>>
>> For that purpose I think that the new
>> drivers/platform/lenovo/wmi-hotkeys.c could maybe expose some
>> notifier and call that for events it does not handle itself
>> and then ideapad-laptop can depend on some function to register
>> a listener on that notifier (1) and register a notifier handler
>> staying out of WMI handling itself.
>>
>> No idea if this is feasible / how clean the end result will be,
>> just brainstorming and saying yes to doing some refactoring of
>> the somewhat messy ideapad-laptop code.
>>
>> Note that https://github.com/systemd/systemd/blob/main/hwdb.d/60-keyboard.hwdb
>> has some mappings for "Ideapad extra buttons" input devices
>> (+ DMI match), so if any of the buttons remapped there end up
>> under the new WMI driver then that should probably give its
>> input device the same name, to make sure those mappings still
>> apply.
> 
> Also see this just posted ideapad-laptop series which does
> something similar for handling YMC events:
> 
> https://lore.kernel.org/platform-driver-x86/20261116-ymc-82yl-v1-0-fac1a2b01a84@rong.moe/

I see that this routes everything through a new lenovo wmi-events
helper which uses a single notifier to which interested parties
like ideapad-laptop can subscribe. I think this models could
be extended to also handle the hotkeys, assuming all the base
bits are moved into the new drivers/platform/lenovo/ dir.

Regards,
 
Hans