Plymouth and Xorg lock up display

[ddawson]

I was using splashutils until just recently. Now I decided to try out Plymouth, but I'm having a couple of issues. First, a minor one: it's not running in the initramfs, even though I'm pretty sure it's installed there. Instead, it runs later. I haven't been able to figure out why, though it's worth noting the same thing seems to have been the case with splashutils. I also recently did a fresh install of Gentoo on another PC, and splashutils is running pretty early there. It's probably some bit of configuration I'm overlooking.

Now, the main, much more serious issue: At the end of the boot sequence, the screen changes back to whatever is in the console, but immediately the display completely freezes! It's not a system hang of any kind; it only affects video output. I can still do things; I just can't see what's happening. Specifically, I can (blindly) log in on the console and do things, and I can ssh in. If I hit Ctrl-Alt-Del, it reboots, and everything goes back to normal.

If I disable Plymouth, everything is fine. If I disable the xdm service, preventing X from starting, everything is fine; I can then start X manually, and everything works. If I switch to another VT before X starts, everything is fine, unless I switch to tty1, at which point it freezes. Also, in this state, I've found that any process that tries to switch the active VT away from tty1 will block indefinitely if it waits for confirmation of the switch; this includes both the chvt command (ran strace on it) and Xorg itself (seen by where the log ends).

It appears that Plymouth and Xorg are conflicting somehow to produce this result. Either the former is lingering too long, or the latter is running too soon, though I'm not sure if that's where the blame lies.

Hardware:
Motherboard: ASRock Z370M Pro4
CPU: Intel Core i3-8100 (Coffeelake), also providing video

Software:
Kernel: Linux 4.19.2-gentoo
Boot system: OpenRC
In case it helps, the output of "emerge --info".

What other info?