laptop_panel.duplicate_video_device quirk?

Ben Liblit liblit at
Wed Jan 2 21:51:20 PST 2008

Julian Sikorski wrote:
> Will this work if two devices are exactly the same?

It is very unlikely that the devices are *exactly* the same.  You just 
need to pick the right feature by which to distinguish them.  For 
example, on my laptop the stuff in /sys/class/backlight/acpi_video0 
doesn't do anything, whereas the stuff in 
/sys/class/backlight/acpi_video1 seems to work.  So I added the local 
quirk attached below, which uses the sysfs path to recognize and kill 
the unwanted acpi_video0 device.

I do *not* claim that my local fix is general, or should be applied 
blindly to anyone else's machine.  It's just a hard-coded fix for my 
box.  But it at least illustrates how one might detect and disable an 
unwanted duplicate video device.

Is it possible to generalize my fix so that it does apply to a variety 
of machines?  I don't know; I haven't tried.  Maybe.  {shrug}
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