Am Wed, 16 Jul 2014 10:35:33 +0200
schrieb Hans de Goede [off-list ref]:

Hi,

On 07/16/2014 10:13 AM, Hans de Goede wrote:

<snip>

quoted

I realize that this does not fix Julian's problem. As I see it
there are 2 separate problems here:

1) backlight control issues on Windows 8 laptops, this is what we
are trying to solve with video.use_native_backlight=1 (and without
using any acpi_osi override)

2) Some component in the stack needs to responds to backlight
key-presses and actually use the backlight control to change the
backlight setting, normally this is done by gnome / kde / unity /
xfce, but what about users not running those? For some of those
users brightness_switch_enabled=1 has been making things work for
them, but that only works if acpi-video controls the backlight,
which it does not do everywhere, and which we want to get away from
for Windows 8 laptops since it is just too broken there.

Note that 2. is not limited to Windows 8 laptops / acpi-video in any
way, we've 23 non acpi-video backlight drivers under
drivers/platform/x86/ alone + the native gpu backlight drivers. So
what we really need is a solution for any laptop not using
acpi-video for backlight control and not running one of the big 4
desktop environments.

Note that we pretty much have the same problem for any acpi event,
power button pressed, lid closed, etc. are all "key press" type
events typically handles by the desktop enviroment (e.g. we don't
automatically suspend on lid-close, we just tell userspace). And we
already have a solution for these type of events when running a
desktop environment which handles them, these get handled by acpid.
So to me it seems that

s/handles/does not handle/  small but important typo.

quoted

the obvious (and one and only right) way to fix this is to teach
acpid to deal with brightness key-presses.

I'm willing to write a patch for acpid to implement this, and then
Julian's setup should just work without needing any special kernel
commandline options.

Julian would that be an acceptable solution for you, and would you
be willing to test such a patch ?

Yes, of course that would be an acceptable solution for me and yes, I
would be willing to test such a patch.

Cheers,
Julian