Backporting skl_update_other_pipe_wm intel drm fixes to the Fedora 4.6 kernel

[Hans de Goede]

Hi Fedora kernel team,

If you look at:

https://retrace.fedoraproject.org/faf/problems/

And look for skl_update_other_pipe_wm there, you will see
that it is completely dominating the problem report stats
(listed 4 times on the first page, 5 times on the second).

As such I'm thinking about backporting the patches:
http://www.spinics.net/lists/intel-gfx/msg95595.html

To the Fedora 4.6 kernel.

Some of the reported problems are only a WARN_ON triggering,
but there are also quite a few cases of actually wrong
watermark settings causing various real problems.

These patches have been around for a long time, but they missed
the 4.6 merge window, and then also the 4.7 merge window, they
are in next now. But IMHO we should grab them now since the
problems they are causing are too big to wait for 4.8
hitting Fedora.

So I would like to backport these to the 4.6 Fedora kernel
and have this completed before we start pushing 4.6 updated
to updates-testing. This way we can use the entire Fedora 4.6
testing phase to also test the backported fixes.

Before I spend time on this, does this sound like a good
plan ?  I've already discussed this within the graphics
team and the consensus there seems to be that this is a good
idea.

Regards,

Hans