v4.14/v4.15-rc1: deferred setup in drm/fb-helper breaks entering pc3

[Thomas Voegtle]

Hello,

with v4.14 I recognized that my file server (headless haswell system)
doesn't enter packages pc3 anymore and only enters pc2 according to
powertop.
In v4.13 the system used pc2 and pc3.

So I bisected that down to:

ca91a2758fcef6635626993557dd51cfbb6dd134 is the first bad commit
commit ca91a2758fcef6635626993557dd51cfbb6dd134
Author: Daniel Vetter <daniel.vetter@xxxxxxxx>
Date:   Thu Jul 6 15:00:21 2017 +0200

    drm/fb-helper: Support deferred setup


Reverting this commit on top of v4.14 and v4.15-rc1 fixes the problem and
the system uses package states pc2 and pc3 again.

Nothing is connected to the VGA and DVI port.
I'm using a kernel without modules on openSUSE 42.3.
I have no "vga=xxx" or something like that on the cmdline.


Thanks,

      Thomas