Packard Bell EasyNote LV need i915.invert_brightness=1

[Daniel Vetter]

On Wed, Jun 26, 2013 at 7:35 PM, Petter Reinholdtsen <pere at hungry.com> wrote:
> [Daniel Vetter]
>>> Is there some other quirk table for acpi that also need to be updated?
>>
>> If the acpi brightness controller is broken, it needs to be quirked
>> away.  For that please file a bug report against the ACPI subsystem.
>
> Right.  Where do I do that?  I can do it if I know what to do. :)
>
>> With that done the automagic fallback rules of the intel DDX driver
>> should expose the "right" backlight interface through the backlight
>> xrandr property. If KDE's powerdevil isn't using that one (and frobs
>> around with the backlight controllers directly) that'd be a bug in
>> kde.
>
> I discovered that by adding acpi_backlight=vendor and keeping the
> i915.invert_brightness=1 setting, the screen went black again.  So
> these settings seem to cancel each other out.  But if I remove
> i915.invert_brightness=1, the screen no longer turn black, and KDE no
> longer turn off the screen when I log in, because instead of using the
> acpi_backlight interface it is using the intel_backlight interface,
> which is not inverted.
>
> So I wonder, perhaps i915.invert_brightness=1 is the wrong quirk for
> this machine?

acpi_backlight=vendor should disable the acpi backlights (you can
check that in /sys/class/backlight), which would mean that userspace
should fall back to intel backlight driver. Can you please check
whether that one works even without the invert_brightness knob? I.e.
not just whether you'll end up with a black screen, but whether
adjusting the backlight also works correctly.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch