I have a Thinkpad X260 running Ubunto 20.04. I just replaced my non-backlight keyboard for one with a backlight and the backlight does not light. All other functions of the keyboard work fine.
Fn+spacebar makes the system act as if it is controlling the backlight (the backlight icon appears on the screen and under options-power the backlight slide bar is shown and moves) but the backlight does not come on.
When in BIOS the Fn green light illuminates and the red mute and microphone mute lights on the function keys light up but not the full backlight.
echo 2|sudo tee /sys/class/leds/tpacpi::kbd_backlight/brightness changes the apparent setting, which corresponds with the setting shown under options, so kbd_backlight is present at that path.
Is there anything I can do to enable the light? Is it possible the keyboard itself is dodgy?
I've updated the BIOS from 1.46 R02ET73W (2020-01-08) to 1.50 R02ET77W (2023-01-18) with no improvement.
sudo lshw -short gives the output:
H/W path Device Class Description
system 20F5S6EH00 (LENOVO_MT_20F5_BU_Think_F
/0 bus 20F5S6EH00
/0/3 memory 64KiB L1 cache
/0/4 memory 64KiB L1 cache
/0/5 memory 512KiB L2 cache
/0/6 memory 4MiB L3 cache
/0/7 processor Intel(R) Core(TM) i7-6500U CPU @ 2.50
/0/8 memory 16GiB System Memory
/0/8/0 memory 16GiB SODIMM DDR4 Synchronous 2133 MH
/0/b memory 128KiB BIOS
/0/100 bridge Xeon E3-1200 v5/E3-1500 v5/6th Gen Co
/0/100/2 display Skylake GT2 [HD Graphics 520]
/0/100/14 bus Sunrise Point-LP USB 3.0 xHCI Control
/0/100/14/0 usb1 bus xHCI Host Controller
/0/100/14/0/8 multimedia Integrated Camera
/0/100/14/1 usb2 bus xHCI Host Controller
/0/100/14.2 generic Sunrise Point-LP Thermal subsystem
/0/100/16 communication Sunrise Point-LP CSME HECI #1
/0/100/17 storage Sunrise Point-LP SATA Controller [AHC
/0/100/1c bridge Sunrise Point-LP PCI Express Root Por
/0/100/1c/0 generic RTS522A PCI Express Card Reader
/0/100/1c.2 bridge Sunrise Point-LP PCI Express Root Por
/0/100/1c.2/0 wlp4s0 network Wireless 8260
/0/100/1f bridge Sunrise Point-LP LPC Controller
/0/100/1f.2 memory Memory controller
/0/100/1f.3 multimedia Sunrise Point-LP HD Audio
/0/100/1f.4 bus Sunrise Point-LP SMBus
/0/100/1f.6 enp0s31f6 network Ethernet Connection I219-V
/0/0 system PnP device PNP0c01
/0/1 system PnP device PNP0c02
/0/2 system PnP device PNP0b00
/0/9 generic PnP device LEN0071
/0/a generic PnP device LEN2014
/0/c generic PnP device INT3f0d
/0/d system PnP device PNP0c02
/0/e system PnP device PNP0c02
/0/f system PnP device PNP0c31
/0/10 scsi1 storage
/0/10/0.0.0 /dev/sda disk 250GB CT250MX500SSD1
/0/10/0.0.0/1 volume 512MiB Windows FAT volume
/0/10/0.0.0/2 /dev/sda2 volume 232GiB Extended partition
/0/10/0.0.0/2/5 /dev/sda5 volume 232GiB EXT4 volume
/1 power 45N1113
/2 power 45N1738
command output image
