Ubuntu
linux package

  1. Bug #1163720
  2. Comment #77

Comment 77 for bug 1163720

Revision history for this message
Jared Dominguez (jared-dominguez) wrote :

I tested on an L322X with _F_HD display and A09 BIOS in UEFI mode.

$ cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-3.11.0-14-generic root=/dev/mapper/ubuntu--vg-root ro splash quiet i915.disable_pch_pwm=0 vt.handoff=7

If I use i915.disable_pch_pwm=0 with the legacy OPROM enabled, I have to run "echo 0 > /sys/class/backlight/intel_backlight/brightness", after which the backlight keys work. If I use i915.disable_pch_pwm=1 with the legacy OPROM _disabled_, the backlight keys work without any additional work.

If I use i915.disable_pch_pwm=0 with the legacy OPROM _disabled_, your test kernel fixes the backlight issue. (However, apparently Saucy's kernel causes really bad graphics corruption if the legacy OPROM is disabled, which is a separate issue.)
And for kicks, i915.disable_pch_pwm=1 with the legacy OPROM disabled brings the system up with the backlight at its lowest setting.