Critical accessibility issue: Please enable Scroll Lock LED as it is needed for keyboard backlight on some keyboards.

[beng-tang]

System Specs Affected:

Hardware: Any IBM PC style 104 or 105 key keyboard with a Scroll Lock key and Scroll Lock indicator LED.

Software: I have found this affecting all versions of Linux Mint that I have tried, ie. 21.1 to 22.1, Cinnamon, MATE and XFCE, and LMDE 6.

Problem:

1. I have weak eyesight and a need keyboard backlight to be able to see the letters on the keys.

2. On my 105 key IBM PC style keyboard, the keyboard backlight is the Scroll Lock LED. That is, the keyboard backlight LED circuit is wired to the Scroll Lock LED. So to toggle the backlight, I press the Scroll Lock key. This works well in DOS or Windows, or at the BIOS Setup screen.

3. Linux does not support the Scroll Lock LED. Because pressing the Scroll Lock key does not turn on the Scroll Lock LED and keyboard backlight in Linux, I cannot see the letters on the keys to type. This makes it hard for me to even type my password at the login screen, let alone do any other kind of typing after logging in.

Partial Workarounds

In X11 sessions, the CLI command "xset led on" will turn on the scroll lock LED and keyboard backlight. This can be put in a shell script which can be linked to Scroll Lock key in keyboard Application Shortcut settings in Linux Mint XFCE.

In order to turn on the keyboard backlight at the login screen so I can see to type the password, it can also be put in Light DM config:
Go to /etc/lightdm/lightdm.conf.d/ in a terminal
sudo touch 71-linuxmint.conf
Edit that file and put in something like

[SeatDefaults]
user-session=xfce
display-setup-script=/etc/init.d/xset-ledon

to point it to the script that runs xset led on. It took me a long time to work out how to do this and it is beyond the skillset of the typical computer user switching from Windows 10 to Linux Mint.

In Wayland sessions I have not found any reliable method to enable the scroll lock LED. Methods involving brightnessctl or
echo 1 > /sys/class/leds/input3::scrolllock/brightness
require sudo to run, which requires typing the password without being able to see the keys. Also display manager scripts under Wayland cannot run as root. Also, the Scroll Lock LED turns off as soon as Caps Lock or Num Lock are pressed.

Feature Request

Please configure Linux Mint to support the Scroll Lock LED out of the box. This is a critical accessibility issue for people like me who have weak eyesight and need the keyboard backlight on to see the letters on the keys and have keyboards where the backlight is the scroll lock LED.

Thanks.

[billyswong]

According to https://forums.linuxmint.com/viewtopic.php?t=445172 one can run

sudo sed -i '60s|.*|modifier_map Mod3 { Scroll_Lock };|' \
/usr/share/X11/xkb/symbols/pc && sudo dpkg-reconfigure xkb-data

to get the scroll lock key functional after reboot. May you test if that works in both X11 and Wayland?

[beng-tang]

Yes I tested your command line and it works! It works in both in X11 and in Wayland. It also works not just in Cinnamon but also in Linux Mint XFCE (have not tested it in MATE).

Scroll Lock key toggles the Scroll Lock LED, and on my keyboard also the keyboard backlight after running that command. It also works at the login screen which is important as I can then turn on the backlight to see the keys to type the password to log in.

I would like to suggest that that fix be somehow added to Cinnamon / Linux Mint so that it is enabled at install time, as it is needed by visually handicapped people who need the backlight to work so they can see the keys, and who have keyboards where the backlight is wired to the scroll lock LED.

It will also be useful, though perhaps less crucial, to anybody who has a keyboard with a scroll lock indicator LED, which is most people who have an IBM-compatible keyboard.

[sonicSMASH]

Im pretty sure that using a TTY (CTRL+ALT+F1) lets you use scroll lock but im not sure

[cplittlfield]

It works with any TTY, so far as I can tell (at least Ctrl + Alt + F1-6), but switching back to the graphical desktop turns Scroll Lock off again.