Kernel Bug Tracker – Bug 11557
Controlling backlight on thinkpad x60
Last modified: 2008-10-16 13:16:33 UTC
Subject : Controlling backlight on thinkpad x60
Submitter : Pavel Machek <email@example.com>
Date : 2008-09-08 15:10
References : http://marc.info/?l=linux-kernel&m=122088987319698&w=4
Handled-By : Matthew Garrett <firstname.lastname@example.org>
This entry is being used for tracking a regression from 2.6.26. Please don't
close it until the problem is fixed in the mainline.
Apparently, this is not a regression from 2.6.26.
On Sunday, 14 of September 2008, Pavel Machek wrote:
> On Sat 2008-09-13 16:13:30, Matthew Garrett wrote:
> > I don't think this is a regression. The correct way to drive this
> > hardware has always been through the ACPI video driver. The fact that
> > thinkpad-acpi would also attempt to drive it was a bug.
> I'm pretty sure thinkpad-acpi is older then ACPI-video. So yes, I
> believe this is a regression, but it may be pretty old one.
hmm, it's not unusual that a laptop has duplicate video devices.
but it's interesting that both of them can control the backlight.
can you attach the acpidump output please?
there are two problems here.
1. backlight control from thinkpad_acpi is not enabled by default any longer. this is why it's marked as a regression.
2. duplicate functional ACPI backlight devices on this platform. this should be fixed by thomas/matthew video patches which are in Andi's acpi test tree now.
1 should not be an issue any more if the new patches are applied. i.e. there should be one ACPI backlight device under /sys/class/backlight/, instead of the thinkpad one.
mark this as a duplicate of bug 11647.
*** This bug has been marked as a duplicate of bug 11647 ***