Here are my modelines for anyone interested.
https://justpaste.it/d33qrLooks like I have to use DP-3 or something instead of VGA-1? Likely because I am running on an APU?
fdaniels@HTPC:~$ ls /sys/class/drm
card0 card0-DP-1 card0-DP-2 card0-DP-3 renderD128 version
I confirmed that this is true, my VGA shows up as DP-3
fdaniels@HTPC:~$ for p in /sys/class/drm/*/status; do con=${p%/status}; echo -n "${con#*/card?-}: "; cat $p; done
DP-1: connected
DP-2: disconnected
DP-3: connected
When I set my resolution in GRUB the PC boots with an error and my VGA port is no longer visible in Ubuntu Display Settings
Nov 22 21:39:40 HTPC kernel: Kernel command line: BOOT_IMAGE=/boot/vmlinuz-5.15.79 root=UUID=b7604868-08b8-403d-85a6-41fb73826c45 ro quiet splash video=DP-3:640x480ieS vt.handoff=7
Nov 22 21:39:42 HTPC kernel: [drm] forcing DP-3 connector on
Nov 22 21:39:42 HTPC kernel: [drm:dc_link_detect_helper [amdgpu]] *ERROR* No EDID read.
If I try to force an EDID (that was generated using switchres, I tried both generic_15 and arcade_15, not sure what the difference is but neither worked).
Nov 22 21:28:22 HTPC kernel: Kernel command line: BOOT_IMAGE=/boot/vmlinuz-5.15.79 root=UUID=b7604868-08b8-403d-85a6-41fb73826c45 ro quiet splash video=DP-3:e drm.edid_firmware=DP-3:edid/arcade_15.bin vt.handoff=7
Nov 22 21:28:24 HTPC kernel: [drm] forcing DP-3 connector on
Nov 22 21:28:24 HTPC kernel: [drm] Got external EDID base block and 0 extensions from "edid/arcade_15.bin" for connector "DP-3"
I don't see any display related errors, but when I boot into Linux only my 4k monitor is visible in Ubuntu Display Settings, and there is no signal to my PVM.
If I remove the kernel video setting my VGA port is visible but appears to be outputting a 480p signal.