Comment # 15 on bug 1004453 from Felix Miata

Created attachment 716701 [details]
systemd-analyze blame from failed attempt to boot directly to KDM3

I put the comment 0 Matrox 550 in a PC running TW that still has
Linux kt400 4.4.0-2-default #1 SMP Thu Jan 21 07:47:10 UTC 2016 (b56b151) i686
athlon i386 GNU/Linux
installed. I updated all except kernel to TW20170305. Xorg 1.19.1 starts to
start with vga=791 included, but this is the Xorg.0.log tail:
# tail Xorg.0.log
[   111.771] (II) evdev: AT Translated Set 2 keyboard: Configuring as keyboard
[   111.771] (**) Option "config_info"
"udev:/sys/devices/platform/i8042/serio0/input/input0/event0"
[   111.771] (II) XINPUT: Adding extended input device "AT Translated Set 2
keyboard" (type: KEYBOARD, id 9)
[   111.771] (**) Option "xkb_rules" "evdev"
[   111.771] (**) Option "xkb_layout" "us"
[   111.773] (II) config/udev: Adding input device PC Speaker
(/dev/input/event3)
[   111.773] (II) No input driver specified, ignoring this device.
[   111.773] (II) This device may have been added with another device file.
[   111.790] (EE)
[   111.790] (EE) Backtrace:

Tail of journalctl -b:
Mar 07 22:53:03 kt400 systemd[1]: Started Process Core Dump (PID 1378/UID 0).
Mar 07 22:53:06 kt400 systemd-coredump[1379]: Process 1369 (X) of user 0 dumped
core.

Startx/KDM3 with 4.4.0 kernel produce only a black screen without or without
vga= on cmdline.

Attached Xorg.0.log is from booting 4.4.0 *with* vga=791 on cmdline.

I've saved systemd coredumps at this juncture on kernel 4.4.0, 4.5.0, 4.6.2 &
4.9.11 in TW20170305 in case they might prove of any use. With 4.4.0, the
coredumps occurred whether or not vga=791 was on cmdline, and Xorg.0.logs
looked similar. With 4.5.0 and newer kernels, coredumps were only generated if
vga=791 was absent from cmdline, and Xorg.0.logs were very different, with
vga=791 present only 6k in size and terminating with no screens have usable
configuration, while without vga=791 they were approaching 38k in size and
terminated as shown above with (EE) Backtrace:. This leads me to suspect this
bug may have arisen in the window between 4.4.0 and 4.5.0.

Without vga= on cmdline and with kernel-default-4.9.11, KDE3 via startx is
again working as expected, though with no /dev/fb* and with vttys stuck at
80x25.

Attempting boot directly to graphical.target KDM3 generates no onscreen errors,
but neither starts the greeter. The journal says only display-manager.service
timed out/failed to start/entered failed state. 
CPU: Single core AMD Athlon XP 2000+ (-UP-) speed: 1674 MHz (max)
Booting multi-user then doing 'systemctl isolate graphical.target' succeeds to
create a usable KDM3 greeter and allow successful login.