I am a bit new here, English is not my native, so I am sorry for any possible misspelling.
I have a very odd problem - my Xiaomi Mi Surface Display 34" (XMMNTWQ34 model) monitor buttons act really strange - instead of calling the monitor OSD, pressing any of 4 present buttons tries to switch to another possible input source (this is even not their function!), but no luck: just 3 seconds of the black screen and it turns back to the initial image. Let me explain how I got into this.
I have a monitor named before, which has 4 input ports: 2 DP and 2 HDMI. There is a PC always connected to the monitor via the DP interface (DP1 to be exact). Today I tried to connect a second PC via HDMI to the HDMI1 port. It went totally good, I was able to switch between PCs using a monitor OSD. But I thought it was too long and complicated to press a dozen buttons on OSD just to change an input source, so started to google any other programmatical methods of doing such thing.
Some fact: there are no drivers for this monitor on the Internet (it actually works at full 3440x1440@144 Hz resolution/refresh rate via DP interface without any trouble, but Windows sees it as "Generic PnP Monitor", so I see no way to fix it without a relevant driver).
I have found that any VESA-compatible monitor has the 0x60 parameter, which means exactly "input source", so altering the value of this parameter switches the input source without the need to call an OSD. I have found that the possible values of this 0x60 parameter for my monitor provided by several utilities are: 0x0F, 0x10, 0x11, and 0x12. But setting any of these values got me no luck - the screen just flashed black and nothing more. Moreover, those utilities showed that the current value of the 0x60 parameter was 0x07 - described as "S-Video 1" input source, and it did not change at any made tries. But my monitor does not even have such input ports!
But I discovered a total disaster a bit later - when I tried to switch the input source via OSD, I was not able to call it - any of the 4 buttons on the monitor was causing a black flash and nothing more! So OSD is now totally unavailable! This is madness. I can't enter the OSD, I can't change the input source without turning off any one of 2 connected PCs, I can't do anything which is supposed to be made via OSD. Rebooting and reattaching of every possible thing has no effect - even with 2 PCs being connected to monitor and waiting to enter a BIOS password (no OS loaded whatsoever): pressing any button on the monitor causes only black flash and nothing more, no OSD called. I guess this is a strictly monitor firmware issue because the OSD worked well until yesterday.
I have absolutely no idea how to solve this, I googled this all day long, but no luck. System restore did not change anything. Please help. Thank you all very much.
Same issue after using ControlMyMonitor App. At the time being, i didn't found any solution to get the OSD back. And I didn't found any solution to factory reset the monitor, I don't know if it's possible.
I strongly discourage users to use any kind of VESA com application on this Xiaomi 34 monitor !
Now, the best solution in order to switch inputs, is to disconnect or shutdown one of the computer connected, ans it will switch automaticaly to the only one remaining. (Or use a VESA script...)