Aaron Lu asked for these things: Please list what backlight control interfaces do you have: # ls /sys/class/backlight acpi_video0 intel_backlight
And test if manually echo a value works: # cd /sys/class/backlight/i915_xxx # cat max_brightness user@Qosmio-X75-A:~$ cd /sys/class/backlight/i915_xxx bash: cd: /sys/class/backlight/i915_xxx: No such file or directory user@Qosmio-X75-A:~$ cd /sys user@Qosmio-X75-A:/sys$ ls block class devices fs kernel power bus dev firmware hypervisor module user@Qosmio-X75-A:/sys$ cd class/backlight/ user@Qosmio-X75-A:/sys/class/backlight$ ls acpi_video0 intel_backlight user@Qosmio-X75-A:/sys/class/backlight$ cd intel_backlight user@Qosmio-X75-A:/sys/class/backlight/intel_backlight$ ls actual_brightness brightness max_brightness subsystem uevent bl_power device power type user@Qosmio-X75-A:/sys/class/backlight/intel_backlight$ cat max_brightness 5273 user@Qosmio-X75-A:/sys/class/backlight/intel_backlight$ cd .. user@Qosmio-X75-A:/sys/class/backlight$ ls acpi_video0 intel_backlight user@Qosmio-X75-A:/sys/class/backlight$ cd acpi_video0 user@Qosmio-X75-A:/sys/class/backlight/acpi_video0$ ls actual_brightness brightness max_brightness subsystem uevent bl_power device power type user@Qosmio-X75-A:/sys/class/backlight/acpi_video0$ cat max_brightness 100 user@Qosmio-X75-A:/sys/class/backlight/acpi_video0$ echo 400 > brightness bash: brightness: Permission denied user@Qosmio-X75-A:/sys/class/backlight/acpi_video0$ sudo echo 400 > brightness bash: brightness: Permission denied user@Qosmio-X75-A:/sys/class/backlight/acpi_video0$ cd .. user@Qosmio-X75-A:/sys/class/backlight$ ls acpi_video0 intel_backlight user@Qosmio-X75-A:/sys/class/backlight$ cd intel_backlight user@Qosmio-X75-A:/sys/class/backlight/intel_backlight$ ls actual_brightness brightness max_brightness subsystem uevent bl_power device power type user@Qosmio-X75-A:/sys/class/backlight/intel_backlight$ cat brightness 5100 user@Qosmio-X75-A:/sys/class/backlight/intel_backlight$ sudo echo 400 > brightness bash: brightness: Permission denied user@Qosmio-X75-A:/sys/class/backlight/intel_backlight$ sudo echo 600 > brightness bash: brightness: Permission denied (see attachment of acpidump.txt) ** Attachment added: "acpidump.txt" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1295141/+attachment/4094303/+files/acpidump.txt -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1295141 Title: Toshiba Qosmio X75-A7298 - Can't Adjust Brightness To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/1295141/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
