Comment 50 for bug 935778

Jowi wrote in comment #29:
"I tried to work around with the acpi_backlight=vendor kernel parameter. To my surprise with this parameter set intel_backlight seems to be used behind the scenes when the Fn-F6/7 keys are pressed. But after resume the backlight stayed off, hence I don't followed this approach any further."

Actually it seems that following this approach just a little further yields a passable solution.

It seems that with acpi_backlight=vendor the backlight is off after a suspend, but it can be turned back on by writing to /sys/class/backlight/toshiba/brightness, and then everything works normally again.

To all those suffering from this bug: there are instructions at that explain how to enable the acpi_backlight=vendor option and set things up with a script that restores the backlight on resume. This fixes the problem for me on my R830.