I have a new Lenovo Ideapad 500S with a fresh Ubuntu 16.04.1 running on it. Unfortunately, the brightness up/down keys don't work. (They work fine in Windows.)
acpi_listen shows me generated events for volume up/down keys, but not for brightness up/down. Running
xev also did not give me any output for the brightness up/down keys.
After editing the
GRUB_CMDLINE_LINUX_DEFAULT line in
/etc/default/grub several times with options like
acpi_osi=, I can confirm that this changes the soft links in
/sys/class/backlight/ and I currently only have
echo <NUM> | sudo tee /sys/class/backlight/intel_backlight/brightness works fine and changes the brightness, and so does changing it from
Settings > Brightness and Lock.
Nothing inside Ubuntu seems to be able to detect these keys, so I'm not sure making any changes in the grub config will matter at all.
Please let me know if someone knows how to fix this and also if any additional information will be useful in debugging this issue.
acpi_osi=Linux acpi_backlight=intel_backlight to the line in grub seems to make the brightness down key generate something in
xev (though nothing in
acpi_listen yet). The output is:
KeyPress event, serial 37, synthetic NO, window 0x3c00001, root 0xd3, subw 0x0, time 391361, (728,884), root:(793,936), state 0x0, keycode 120 (keysym 0x0, NoSymbol), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False KeyRelease event, serial 37, synthetic NO, window 0x3c00001, root 0xd3, subw 0x0, time 391368, (728,884), root:(793,936), state 0x0, keycode 120 (keysym 0x0, NoSymbol), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False
$ lspci -nnk | grep -iA2 vga 00:02.0 VGA compatible controller : Intel Corporation Sky Lake Integrated Graphics [8086:1916] (rev 07) Subsystem: Lenovo Skylake Integrated Graphics [17aa:3828] Kernel driver in use: i915_bpo