Re: [PATCH 1/1] drm/i915: Allow specifying a minimum brightness level for sysfs control.

[Danny Baumann <dannybaumann@web.de>]

Hi,

> Thus far our assumption always was that the acpi backlight works better
> than the intel native backlight. So everything only uses the intel
> backlight if there's no other backlight driver by default.
>
> So if I should merge this as a general solution for Windows 8 machines not
> working properly, we first need to figure out what windows does on these
> machines and either disable the acpi backlight or adapt it.

I fully agree to that. Making acpi_video control usable is preferable 
over using intel_backlight. As I lack the detail knowledge about the 
ACPI video stuff, I'd be great of one (or some) of you guys could look 
at the mentioned bug report ([1]) and comment on what the problem might 
be. I have added the basic needed information already and would be happy 
to provide any needed debugging info.

> Adding more kernel options is not a viable solution for the backlight mess
> imo.

Actually I'm fine with hardcoding the percentage as well ;) I just 
figured it might make sense to make it controllable for special-case 
uses, while still making intel_backlight usable for the 'normal' use case.

Regards,

Danny

[1] https://bugzilla.kernel.org/show_bug.cgi?id=55071