the main monitor ends up black

[GlowInTheDark]

Pi4, 4G, latest Buster, installed via the latest PINN, dual monitor system.

But by no means limited to the above set of circumstances - seems to happen always on this particular hardware config with Buster.

The problem is that when ever the machine is cold booted (from power on), the main monitor ends up black. There is a X desktop visible on the second monitor, but no lxpanel or icons, so you can't do anything (except see below). Rebooting fixes the problem - system comes up correctly on the reboot. But it always fails on the cold boot.

Note: You can get a shell going on the second monitor by doing the following steps:

1) Ctrl/Alt/F2
2) login on tty2
3) Execute: DISPLAY=:0.0 lxterminal
4) Alt/F7 (or F1 - see below) to get back to the desktop - where the shell will now be running.

Also note: It seems that somewhere along the way, they may have made the switch to running the GUI on tty1 instead of on tty7. As noted by me elsewhere, the latest cutting-edge versions of Debian Linux now run the GUI on tty1 instead of tty7. This is done in the name of "security". There are certain circumstances in which Raspbian is now doing this (I have not investigated thoroughly enough to be able to authoritatively state what those conditions are, but I have definitely seen it in today's testing).

[kerry_s]

sounds like screen blanking is kicking in or a faulty hdmi wire?
you must have a old copy of raspbian desktop, cause it's defiantly on tty7, i just checked on mine this is a fresh install a couple of hours old.

try swapping the hdmi cables for the monitors see if 0 comes on, try with just 1 screen?

[GlowInTheDark]

Previous response is all irrelevant.

I should add that I've seen many similar references to this problem on the forum, so the problem is by no means unique to me. It's not a problem at my end. I just hope the developers can fix it - although, to be fair, it is merely an annoyance, not a show stopper, since it goes away on the reboot. It is just annoying having to boot twice after switching SD cards (I.e., when I need to do a full poweroff).

[FTrevorGowen]

Previous response is all irrelevant.

I should add that I've seen many similar references to this problem on the forum, so the problem is by no means unique to me. It's not a problem at my end. I just hope the developers can fix it - although, to be fair, it is merely an annoyance, not a show stopper, since it goes away on the reboot. It is just annoying having to boot twice after switching SD cards (I.e., when I need to do a full poweroff).

OOC, after shutting down (full poweroff) do you physically remove all power "sources" (this may include HDMI connections, externally powered USB hubs etc.? Some displays, possibly only TV's, trickle enough "back power" to cause the PoWeR led to flash at ~10s intervals but, AFAICT, only if a USB C power source, switched off at the A.C. mains, is still physically connected - ie. a latent, capacitive, slow discharge effect?)
Trev.

[jamesh]

Previous response is all irrelevant.

There are ways of replying to people to say that they may be wrong in their assessment/help. This is an example of how it shouldn't be done. A simple statement that some would find rude, with no explanation of why. We can do better.