Comment # 13 on bug 1188954 from Felix Miata

(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.

As previously noted, this has turned out *not* to be limited to AMD. After
reproducing this on a second Kaby Lake (gb250) I did some experimenting.

This is typical content of my grub.cfg linu lines where this reproduces:
    mitigations=auto consoleblank=0 video=1440x900@60 5
Changing it on gb250 to:
    mitigations=auto video=1440x900@60 5
*sometimes* avoids "(EE) open /dev/dri/card0: No such file or directory",
resulting in expected startup.

Other times, the screen is black as noted in comment 0, while other times,
focus returns to the login prompt on tty1.

I switched back to the comment #12 Kaby Lake (host ab250), tried the same
things, and cannot get X to start on first try no matter what. There's also
this:
# systemd-analyze
Startup finished in 17.795s (firmware) + 5.243s (loader) + 1.458s (kernel) +
1.406s (initrd) + 2.985s (userspace) = 28.889s
graphical.target reached after 2.961s in userspace

It seems consoleblank=0 on kernel command line *can* somehow affect timing of
the KMS kernel module loading, whether it be i915, amdgpu or radeon, but the
real or main problem must be that each KMS module simply is not getting loaded
soon enough.

Is there anything that can advance KMS module loading?