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View Full Version : [SOLVED] 18.04 boot hangs after GRUB; error with dell::kbd_backlight



windfix
June 19th, 2018, 08:02 PM
Posting this to assist any others with installations on Dell hardware. My fresh install of 18.04 on a Dell Studio 1440 worked fine until the first reboot; it then hung after the GRUB menu.

I pressed "e" during GRUB menu to edit the kernel parameters and removed "quiet" and "splash" so I could see all messages during boot. My machine was hanging on a message about leds:dell::kbd_backlight

Eventually, I found that there is a persistent bug in the kernel (https://bugzilla.kernel.org/show_bug.cgi?id=107651) relating to Dell keyboard backlights, dating back several years and yet unfixed. Thanks to Iván Jiménez, who pinned-down what was happening, and provided a work-around using

systemctl mask systemd-backlight@leds\:dell\:\:kbd_backlight.service

He notes that the problem is associated with the presence of a file

/var/lib/systemd/backlight/platform-dell-laptop:leds:dell::kbd_backlight

Steps:
From GRUB, select advanced options, then Root Shell.
Do:

mount -o remount,rw /
rm /var/lib/systemd/backlight/platform-dell-laptop:leds:dell::kbd_backlight
systemctl mask systemd-backlight@leds\:dell\:\:kbd_backlight.service
reboot

oygle
August 12th, 2018, 12:53 PM
Steps:
From GRUB, select advanced options, then Root Shell.
Do:

mount -o remount,rw /
rm /var/lib/systemd/backlight/platform-dell-laptop:leds:dell::kbd_backlight
systemctl mask systemd-backlight@leds\:dell\:\:kbd_backlight.service
reboot

Thanks. I will try your fix tomorrow. I have a Dell laptop and think it may be this problem. See https://ubuntuforums.org/showthread.php?t=2397910

oygle
August 13th, 2018, 12:30 AM
Before I do that fix, as I have also noticed the system waiting sometimes at BIOS, it might be wise to update the BIOS. An article at https://www.dell.com/support/article/au/en/audhs1/sln171755/updating-the-dell-bios-in-linux-and-ubuntu-environments?lang=en