Re: [PATCH] laptop_panel.brightness_in_hardware: add all Asus laptops

[Alan Jenkins <alan-jenkins@tuffmail.co.uk>]

Matthew Garrett wrote:
> The problem in that case is that the kernel changes the backlight for 
> us. The lack of consistency on this front makes life somewhat harder. 
>
> In terms of the "Some hardware sends keyboard events but also changes 
> the brightness", I'm working on a cleaner solution for this. The easiest 
> would seem to be to generate a uevent when the backlight is changed, 
> which would then allow userspace to pop up UI even though the key press 
> events aren't propagated. It would seem to deal with the Eee (and older 
> Thinkpad) cases quite nicely, but does require some more code in 
> userspace.
>   

Ok. Maybe it's trivial or "niche", but I really appreciate this. I think 
it's the only remaining issue I have with my EeePC :-).

I just saw the patch to generate uevents for the acpi video driver. It 
looks like it still generates KEY_BRIGHTNESSDOWN. Are you planning a 
followup patch, to suppress the input events when 
brightness_switch_enabled == 1?

Equally, w.r.t patch 3, I don't think eeepc-laptop, should generate 
brightness events on the *input* device anymore.

The rationale is that KEY_BRIGHTNESSDOWN is a user request to increase 
brightness. In these cases, the firmware/driver has already increased 
the brightness. We've notified userspace via the backlight device. So we 
shouldn't pass the request on to userspace; it has already been acted 
upon. If we still generate KEY_BRIGHTNESS*, userspace has to guess 
whether or not the change has already been applied. If there is too much 
latency, it guesses wrong :-(.

Thanks!
Alan