Lars Noodén wrote on 18/05/17 15:14:
> On 05/18/2017 01:21 AM, Gregory Nowak wrote:
>> On Wed, May 17, 2017 at 03:48:14PM +0300, Lars Noodén wrote:
>>> Any hints would be appreciated.
>>
>> Did you try what I suggested:
>> <https://lists.dyne.org/lurker/message/20170504.220911.f8f21b53.en.html>
>>
>> Greg
>
> Yes, thanks, but that neither have any effect on the screen's backlight.
>
> $ cat /proc/cmdline
> BOOT_IMAGE=/boot/vmlinuz-3.16.0-4-amd64
> root=UUID=5a117781-af00-4960-aff2-f711d5652784 ro acpi-backlight=vendor
> acpi_osi=Linux
>
> The keyboard backlight seems to work find regardless of the settings if
> that's any clue.
>
> /Lars

Unless you've been there already,
https://wiki.archlinux.org/index.php/Toshiba_Satellite_R830
has a couple of suggestions. Especially if that's your model.

Ralph.