random hangs with dual GeForce 8400 GS setup
Sometimes all drawing on the screen except for the cursor simply stops. Moving the mouse will cause the cursor to move, but no clicks seems to be processed. Ctrl+alt+fX doesn't switch to a terminal, caps lock doesn't cause its keyboard light to come on, num lock doesn't cause its keyboard light to come on. SSH access still works fine. When strace'ing the server, it appears to be stuck in an infinite loop (same system call over and over again, log snippet attached).
Also attached is the output of 'dmesg', 'lspci -vvv', and /var/log/Xorg.0.log.
dmesg-log lspci-log Xorg.0.log
These hangs have highly variable lengths of time between them. Sometimes it will go a month without a hang, sometime it will go a day. I have never come back to my running system and found the X server hanging, it always happens while I am doing something, usually with emacs (though that's not saying much). So far it has never recovered, always requiring a restart of the server.
If it matters, I'm using the two GPUs to drive three displays. I do this by running
xrandr --setprovideroutputsource 1 0
I don't remember why that's necessary, but apparently a single one of those GPUs doesn't have enough crts or something for 3 independent displays. I have integrated AMD graphics (the stuff that comes with the A10-7850k), but don't use them because they require proprietary firmware and I'm using linux-libre.
My distribution is Guix System, freshly reconfigured with commit 0ef7e44439c6e1b87bea5cdc39f1fa07e62edba4. The kernel is linux-libre 5.4.13. My xorg-server is version 1.20.7, display manager is slim 1.3.6, and my window manager is i3-wm 4.17.1.
I will look into acquiring debugging symbols for the X server so that I can attach gdb to it effectively. In the meantime, here's a backtrace without them:
Sorry if this is a duplicate of one of the many "server hangs" issues, I read several of them and couldn't find any that quite matched what I was experiencing. Let me know if any additional information can help.