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

[Matthew Garrett <mjg59@srcf.ucam.org>]

On Thu, Jul 16, 2009 at 11:22:47PM +0100, Alan Jenkins wrote:

> 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?

I didn't want to change the behaviour of the driver with existing 
userspace, but yes, I agree that that's the correct behaviour. To make 
it consistent with everything else it should probably also default to 
brightness_switch_enabled = 0 (and we ship it that way in Fedora), but 
again, compatibility.

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

Right.

> 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 :-(.

Absolutely. The other thing that needs doing is for dell-laptop to 
consume the brightness keys, or alternatively for us to remap them on 
Dells. Right now (in the worst case) we're getting two sets of them.

-- 
Matthew Garrett | mjg59@srcf.ucam.org