[Intel-gfx] screen freeze with 5.2-rc6 Dell XPS-13 skylake i915

[James Bottomley]

The symptoms are really weird: the screen image is locked in place. 
The machine is still functional and if I log in over the network I can
do anything I like, including killing the X server and the display will
never alter.  It also seems that the system is accepting keyboard input
because when it freezes I can cat information to a file (if the mouse
was over an xterm) and verify over the network the file contents. 
Nothing unusual appears in dmesg when the lockup happens.

The last kernel I booted successfully on the system was 5.0, so I'll
try compiling 5.1 to narrow down the changes.

James