ddcutil

I love this approach, but a few years ago I tried it very unsuccessfully with my Xiaomi Mi 34" ultrawide. By very unsuccessfully, I mean that the commands to change input didn't work. I can't remember if they did nothing or crashed the monitor, but subsequent investigation led me to realise I was lucky not to brick it, as some people found certain commands cause non-recoverable issues on that monitor! So, I suggest caution in the form of maybe checking that others have successfully used DDC commands on your particular model. https://github.com/rockowitz/ddcutil/issues/153

I did that at home. But I needed to try several KVMs until I found one which was stable. And I hate all the cables. I agree that the industry hates its consumers and likes to mess things up. CEC never always quite the same. Not supported on many GPUs etc. I do not want to appear to condone LG. But actually (sorry!) some supoort[0] it using DDC side channels (0x50 rather that 0x51). But I agree it is painful. Yet I prefer it over my cable spaghetti. [0] https://github.com/rockowitz/ddcutil/wiki/Switching-input-so...

Or they are just simply not on the happy path. For example, my laptop has been running KDE just fine for years, but my attempts to switch to Linux on my desktop today have turned into a project, as plasma, steam[1], discord, and sometimes kde_powerdevil[2] are crashing every time my monitors turn off. [1] Might be https://gitlab.gnome.org/GNOME/gtk/-/issues/5984 [2] https://github.com/rockowitz/ddcutil/issues/556

There are some tools out there that will allow you to bind hotkeys (or at least provide a widget) to send brightness-adjustment commands via DDC/CI over the HDMI/DP cable to your desktop monitor. This may improve your UX. My 2015 and 2021 Dell monitors both support the functionality, with differing degrees of finesse. Non-exhaustive list: Linux: https://github.com/ddccontrol/ddccontrol || https://github.com/rockowitz/ddcutil macOS: https://github.com/MonitorControl/MonitorControl Windows: https://github.com/emoacht/Monitorian

Similar tool for macOS that also controls built-in displays and Apple monitors: https://github.com/MonitorControl/MonitorControl Not aware of a similarly polished GUI tool on linux, but I use this: https://github.com/rockowitz/ddcutil It's been super convenient having found all these tools (I use all 3!) for software control of monitors recently.

On Linux, there is a very comprehensive CLI utility called ddcutil: https://github.com/rockowitz/ddcutil The same author also made some kind of UI for it but I haven't used it so I don't know how it looks or performs: https://github.com/rockowitz/ddcui

Yeah, this is almost certainly the same bug. Some more info here [1] [2] [3]. In my case, using the second direct HDMI cable like you did was a non-starter because my Thinkpad only supports 4k at 30 Hz via the built-in HDMI port (!), vs. 4k at 60 Hz if you use the Thunderbolt port or a dock / adapter connected to that port. 30 Hz gave me eye strain after less than 5 minutes. [1] https://gitlab.freedesktop.org/drm/intel/-/issues/37 [2] https://github.com/rockowitz/ddcutil/issues/11 [3] https://github.com/rockowitz/ddcutil/issues/146

I use a USB host-side switch [0] to quickly move my keyboard and mouse between my desktop and my laptop's docking station, since my 4k monitor already supports multiple inputs, and 4k capable KVMs are expensive and buggy. In order to make the switch, I push one button on the USB switch, and then select the next input on my monitor (four button presses using the monitor's OSD). There's a great little tool called ddcutil [1] that allows you to send commands to your monitor via the i2c bus embedded in your HDMI/DisplayPort connection, so I tried to write a script to do the monitor input swap on either a key binding or after detecting the appropriate USB event. It almost worked. My monitor only listens to the i2c bus of the selected input, so I need to run this script on both my desktop and laptop rather than just on the desktop. But apparent

The equivalent for Linux users are ddccontrol and ddcutil. https://github.com/ddccontrol/ddccontrol https://github.com/rockowitz/ddcutil