Am 11.10.24 um 17:26 schrieb Pavel Machek:

Hi!

1.
https://lore.kernel.org/all/6b32fb73-0544-4a68-95ba-e82406a4b...@gmx.de/
-> Should be no problem? Because this is not generally exposing wmi
calls, just mapping two explicitly with sanitized input (whitelisting
basically).
It would be OK to expose a selected set of WMI calls to userspace and 
sanitizing the input of protect potentially buggy firmware from userspace.

I don't believe this is good idea. Passthrough interfaces where
userland talks directly to hardware are very tricky.

Regarding the basic idea of having a virtual HID interface: i would prefer to 
create a illumination subsystem instead, but i have to agree that we should be 
doing this
only after enough drivers are inside the kernel, so we can design a
suitable interface for them. For now, creating a virtual HID
interface seems to be good enough.
I have an RGB keyboard, and would like to get it supported. I already
have kernel driver for LEDs (which breaks input functionality). I'd
like to cooperate on "illumination" subsystem.

Best regards,
                                                                Pavel

Sorry for taking a bit long to respond.

This "illumination" subsystem would (from my perspective) act like some sort of 
LED subsystem
for devices with a high count of LEDs, like some RGB keyboards.

This would allow us too:
- provide an abstract interface for userspace applications like OpenRGB
- provide an generic LED subsystem emulation on top of the illumination device 
(optional)
- support future RGB controllers in a generic way

Advanced features like RGB effects, etc can be added later should the need 
arise.

I would suggest that we model it after the HID LampArray interface:

- interface for querying:
 - number of LEDs
 - supported colors, etc of those LEDs
 - position of those LEDs if available
 - kind (keyboard, ...)
 - latency, etc
- interface for setting multiple LEDs at once
- interface for setting a range of LEDs at once
- interface for getting the current LED colors

Since sysfs has a "one value per file" rule, i suggest that we use a chardev 
interface
for querying per-LED data and for setting/getting LED colors.

I do not know if mixing sysfs (for controller attributes like number of LEDs, 
etc) and IOCTL
(for setting/getting LED colors) is a good idea, any thoughts?

Thanks,
Armin Wolf

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