Fwd: Brightness on HP EliteBook 8460p

[Alex Deucher]

On Tue, Jul 31, 2012 at 12:03 PM, Pali Rohár <pali.rohar at gmail.com> wrote:
> On Tuesday 31 July 2012 17:49:32 Luca Tettamanti wrote:
>> I'm putting back the CC and adding Alex.
>>
>> On Tue, Jul 31, 2012 at 5:07 PM, Pali Rohár
> <pali.rohar at gmail.com> wrote:
>> > Thanks, now working. When I write to acpi video brightness
>> > file it change brightness and in dmesg is:
>> >
>> > [   47.200998] [drm:radeon_atif_handler], event, device_class
>> > = video, type = 0xd0
>> > [   47.201102] [drm:radeon_atif_get_sbios_requests], SBIOS
>> > pending requests: 0x80
>> > [   47.201104] [drm:radeon_atif_handler], ATIF: 1 pending
>> > SBIOS requests
>> > [   47.201105] [drm:radeon_atif_handler], Changing brightness
>> > to 11
>>
>> Great! I'll send an updated patch to Alex soon.
>>
>> > I think that acpi only sent event about brightness key
>> > pressed, because nothing happened when I pressed it.
>> >
>> > Also for windows is needed special HP application (hp hotkey)
>> > for brightness keys. Without it brightness keys not working
>> > too...
>> I've looked at hp-wmi: the hotkey is indeed dispatched via WMI
>> (hp-wmi) so you need something in userspace (KDE, Gnome, etc)
>> to respond to that key press.
>>
>
> No, when I rmmod hp-wmi brightness keys still generate events.
> And when I disable acpi then brightness keys do not generate
> events but adjust brightness automatically (by BIOS).
>
> I think that hp-wmi on my notebook only handle bluetooth & wifi
> rfkills and ALS switch. All button working without hp-wmi too.
>
>> > And there is one problem with /sys/class/backlight/radeon_bl.
>> > When I enable Ambient Light Sensor which auto adjust
>> > brightness based on sensor data, writing value 0 (min) or
>> > 255 (max) to /sys/class/backlight/radeon_bl/brightness turn
>> > off display.
>> Ok, that's weird. 0 turns off the panel by design, 255 should
>> not...
>
> But when ALS is disabled 0 did not turn display off.

0 only turns off the backlight, not the panel itself.  Is the
backlight still partially on or is it just the actual panel (timing
and image)?

Alex