ddcci-driver-linux VS display-switch

There is an out-of-tree kernel module that exposes the DDC-CI interface as a regular brightness control, so any laptop-oriented brightness control tool will work afterwards.

Those tools use the kernel backlight system, which doesn't support external monitors out of the box. It's the same with Xorg. You can get the ddcci-backlight driver: https://gitlab.com/ddcci-driver-linux/ddcci-driver-linux/

To add to this: if you install ddcci-driver-linux GNOME should be able to control your brightness again. This removes the need for any extensions, and it's what I've been using for my monitor for the last few years.

There is an out of tree kernel module doing just that (integrating ddc/ci, the control channel for external monitor*, with the backlight system). And someone is working on upstreaming it

This is kinda a self promotion but for the brightness issue https://gitlab.com/ddcci-driver-linux/ddcci-driver-linux may fix it. Or https://gitlab.com/YusufKhanAbdulHalim/ddcci-driver-linux/-/tree/master may fix it(if the first one doesnt work use the second one).

There is an unofficial Linux kernel module that allows userspace control of brightness (in a similar way to how laptop brightness is controllable):

https://gitlab.com/ddcci-driver-linux/ddcci-driver-linux

I’ve been using display-switch[0] for this for a while now. No problems whatsoever. Works on windows/mac/linux.

[0] https://github.com/haimgel/display-switch

Now it just need to be combined with something like https://github.com/haimgel/display-switch to do a DDC/CI monitor input switch as the USB activity moves around.

With a device like this you'd be missing the on_usb_connect event, but presumably you could do something (a special HID device button, an extra device id appearing, who knows) to make it work.

The best option I've found is to hook both computers up to a USB-only KVM, and plug them in via separate video cables to the monitor. Then set up the computers to tell the monitor to change inputs (via DDC commands, which most but not all monitors support) when you change devices on the KVM

There's software to help do this automatically (https://github.com/haimgel/display-switch)

Cynical footnote: PC users can continue to enjoy https://github.com/haimgel/display-switch while Mac users need to buy a 300 USD device. That's the Mac experience for you :D

There's a workaround in https://github.com/haimgel/display-switch now for M1 Macs. In general, you made your bed by buying a Mac, sleep in it.

Oops I missed that https://github.com/haimgel/display-switch

Then we will run https://github.com/haimgel/display-switch to have the monitors switch inputs when you use the USB switch.