Comment 14 for bug 764195

The nvidiabl driver now detects ThinkPad T510s with model 4313CTO. This will not allow gnome-power-manager to control the backlight, but at least the keys will work....sort of. With autodetected values, brightness can be turned down all the way, but can only be set to a proper maximum by switching to a VT and turning the brightness down a notch. If anyone would like to play around with backlight values, the instructions below will get them set up. nvidiabl's source can be modified to work with other ThinkPad models as well.

ACPI backlight control must be set to vendor, the thinkpad_acpi module's brightness controls must be disabled and the brightness keys must be bound using acpi events.

ACPI backlight controls can be set to vendor by setting 'GRUB_CMDLINE_LINUX_DEFAULT="acpi_backlight=vendor"' in /etc/default/grub and then running update-grub.

thinkpad_acpi's brightness controls can be disabled by creating /etc/modprobe.d/thinkpad_acpi.conf and adding the line "options thinkpad_acpi brightness_enable=0".

nvidiabl source can be obtained from https://github.com/guillaumezin/nvidiabl , then installed by dkms. The scripts "nvidia_backlight_down.sh" and "nvidia_backlight_up.sh" should be copied from the scripts folder to /etc/acpi.

Then the brightness keys can be bound to those scripts by creating/filling the following files:

/etc/acpi/events/lenovo-4313cto-brightness-down
event=video LCD0 00000087 00000000
action=/etc/acpi/nvidia_backlight_down.sh

/etc/acpi/events/lenovo-4313cto-brightness-up
event=video LCD0 00000086 00000000
action=/etc/acpi/nvidia_backlight_up.sh

ACPI events were determined using acpi_listen.