Comment # 24 on bug 1188954 from Felix Miata

Created attachment 862373 [details]
systemd-analyze blame

This 475 line attachment is from today's fresh installation. I spent all day
yesterday and the first hours of today beating my head against this wall with
this PC's previous 15.4, an upgrade from 15.3 many moons ago then ending with
kernel-default-5.14.21-150400.22.1 as latest kernel, then three separate
attempts to upgrade from 15.3 again, before deciding on a fresh start.

(In reply to Stefan Dirsch from comment #7)
> Ok. If it fails only during initial X startup, this looks like a timing
> issue, i.e. kernel module is not being initialized in time before X gets
> started. Maybe amdgpu kernel module is missing from initrd, but radeon is
> (since it's the default driver), i.e. adding amdgpu to initrd may help (if
> it's really missing).

On 15.4 post-kernel-default-5.14.21-150400.22.1, the Kaveri [Radeon R7
Graphics] chip-ID: 1002:130f PC is stubbornly refusing to load a kernel
graphics module before X tries its first start on each boot. XDM won't auto
restart, so I get either solid black screen, or a tty1 login prompt, depending
on what linu line parameters are used, and/or which display drivers are
configured, and/or whether I have validly reconfigured dracut for graphics
module loading, and/or I've blacklisting of radeon in /etc/modulesload.d/.

# systemd-analyze critical-chain
...
graphical.target @4.227s
������������������multi-user.target @4.226s
  ������������������kbdsettings.service @2.171s +2.055s
    ������������������basic.target @2.154s
      ������������������sockets.target @2.154s
        ������������������telnet.socket @2.154s
          ������������������sysinit.target @2.148s
            ������������������systemd-backlight@backlight:acpi_video0.service @3.476s +7ms
              ������������������system-systemd\x2dbacklight.slice @3.271s
                ������������������system.slice
                  ������������������-.slice

Questions:

1-How do I guarantee earliest possible loading of whatever kernel graphics
module is needed or wanted, whether radeon or amdgpu? Is force_drivers+="
amdgpu " in a file of any name in /etc/dracut.conf.d/ sufficient to ensure
loading amdgpu comes first? Solely? Is omit_drivers+=" radeon " needed as well?

2-Does initrd by default include whatever blacklisting is contained in
/etc/modprobe.d/? Is "blacklist radeon" in any file in this directory
sufficient? Do filenames here need to end in .conf to be utilized?

3-Could a delay of first X start on custom want or after existence of
/dev/dri/card0: in /usr/lib/systemd/system/display-manager.service work?
Shouldn't that already be happening?

Googling early graphics loading has been getting me nothing but *NVidia* and/or
Youtubes. :( 15.3 & TW are behaving perfectly using only amdgpu, without any
heroics, on same PC.