This bug is caused by BIOS reporting zero in _BQC when system boots up. As a result, kernel will set the brightness to zero and the screen is dimmed to complete black.
The attached patch adds a quirk to ignore the initial _BQC value and set the brightness to max. ** Patch added: "0001-ACPI-video-ignore-BIOS-initial-backlight-value-for-H.patch" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1167760/+attachment/3666504/+files/0001-ACPI-video-ignore-BIOS-initial-backlight-value-for-H.patch -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1167760 Title: [HP 1000] Screen backlight is off after startup. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1167760/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
