Original Summary:
[simpledrm][UEFI] Black screen until KMS engages, then system freezes, when KMS
is defective and plymouth=0

Background:
Asus has been a nightmare of asking for more info because my Rocket Lake
motherboard will not boot any Linux OS unless the displays connected to the
motherboard's 3 graphics connectors are limited to one. When I try, it freezes,
apparently at the point when KMS tries to engage. If I connect additional
displays after boot is complete, then all works as expected. See bug #1193640
and https://gitlab.freedesktop.org/drm/intel/-/issues/4762

When using Tawai's simpledrm kernels on TW and Plymouth is not installed, and
with more than one display connected to this B560M-A motherboard's video output
connectors, on proceeding from Grub menu, screens instantly turn black, and
stay that way, with the system frozen and no possibility to remote login. With
standard kernel, proceeding from Grub, the usual boot messages display until
apparent KMS engagement, when the PC freezes.

Using simpledrm should not result in instant and persistent black screen on
proceeding from EFI Grub.

Info following was captured during 15.3 multi-user boot with only one display
connected:
# inxi -Cyz
CPU:
  Info: 6-Core model: 11th Gen Intel Core i5-11400 bits: 64 type: MT MCP
  cache: L2: 3 MiB
  Speed: 801 MHz min/max: 800/4400 MHz Core speeds (MHz): 1: 800 2: 801 3: 801
  4: 808 5: 802 6: 801 7: 846 8: 837 9: 846 10: 800 11: 844 12: 846
# inxi -GMSayz
System:
  Kernel: 5.3.18-59.37-default x86_64 bits: 64 compiler: gcc v: 7.5.0
  parameters: BOOT_IMAGE=/boot/vmlinuz root=LABEL=<filter> noresume
  ipv6.disable=1 net.ifnames=0 consoleblank=0 3 nomodeset
  Console: pty pts/0 Distro: openSUSE Leap 15.3
Machine:
  Type: Desktop System: ASUS product: N/A v: N/A serial: N/A
  Mobo: ASUSTeK model: PRIME B560M-A v: Rev 1.xx serial: <filter>
  UEFI: American Megatrends v: 1203 date: 10/27/2021
Graphics:
  Device-1: Intel RocketLake-S GT1 [UHD Graphics 730] vendor: ASUSTeK
  driver: N/A alternate: i915 bus-ID: 00:02.0 chip-ID: 8086:4c8b
  class-ID: 0300
  Display: server: X.org 1.20.3 driver: loaded: modesetting
  unloaded: fbdev,vesa alternate: intel
  Message: Advanced graphics data unavailable for root.