Bug#868884: src:linux: dell::kbd_backlight Causes Powerdevil Lockup on Resume

[bw <bwtnguy@yahoo.com>]

Package: src:linux
Followup-For: Bug #868884

This file shouldn't exist, as the machine has no kbd backlight:

/sys/devices/platform/dell-laptop/leds/dell::kbd_backlight

Kde power management thinks it needs to restore it on resume.  The
only workaround I could find is remove powerdevil packages.

Nothing can be removed, added or edited.  I read a little about sysfs,
but I think I'll leave it alone.  I thought maybe it could be a bad BIOS,
maybe an ACPI issue, not really sure how it can get solved.

/sys/devices/platform/dell-laptop/leds/dell::kbd_backlight# ls -l
total 0
-rw-r--r-- 1 root root 4096 Nov 14 18:26 brightness
lrwxrwxrwx 1 root root    0 Nov 15 13:02 device -> ../../../dell-laptop
-r--r--r-- 1 root root 4096 Nov 14 18:26 max_brightness
drwxr-xr-x 2 root root    0 Nov 15 13:02 power
-rw-r--r-- 1 root root 4096 Nov 15 13:02 start_triggers
-rw-r--r-- 1 root root 4096 Nov 15 13:02 stop_timeout
lrwxrwxrwx 1 root root    0 Nov 14 18:26 subsystem -> ../../../../../class/leds
-rw-r--r-- 1 root root 4096 Nov 15 13:02 trigger
-rw-r--r-- 1 root root 4096 Nov 14 18:26 uevent

-- System Information:
Debian Release: 9.2
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 4.9.0-4-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE= (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)