On Wed, Jun 26, 2013 at 7:35 PM, Petter Reinholdtsen pere@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