regression on Carrizo display bringup

[Tom St Denis]

Hi all,

Found when testing the tip of drm-next on my A12-9800 Carrizo.

[root at carrizo linux]# git bisect good
138a3358c17918bb5cd5aa1ea9e8760ac69c515d is the first bad commit
commit 138a3358c17918bb5cd5aa1ea9e8760ac69c515d
Author: Yongqiang Sun <yongqiang.sun at amd.com>
Date:   Tue Nov 7 11:01:34 2017 -0500

     drm/amd/display: Optimize programming front end

     In case of update type is medium, optimize squence,
     reduce programing time.

     Change-Id: Ib1793408897b0c4d4a64434c239c3703d43e83d9
     Signed-off-by: Yongqiang Sun <yongqiang.sun at amd.com>
     Reviewed-by: Tony Cheng <Tony.Cheng at amd.com>
     Acked-by: Harry Wentland <harry.wentland at amd.com>

:040000 040000 8d62da91eddb89e8152b46cce5c1c8aa8edb80bf 
c377c5887076041e5a61640e78be756af48001ff M      drivers


When I load amdgpu I get a screen that is mostly white with red bars and 
then some noise.  Nothing shows up in my dmesg log that is specific to 
this error.

When I load X it seems like it's working though.  I do get noise when I 
resize mpv from full to windowed (and back) but it goes away.


Tom