[Freedreno] "blue flashes" on hdmi display..

[Rob Clark]

I think I've fixed a couple issues which were causing underflow errors
which would appear as a blue flash.  I was not seeing the issue very
much, although others had reported seeing it more.  The only place I
could reliably reproduce it (and which is now fixed) was when hw
cursor is first enabled.

Kernel (which is based on top of hdmi-audio branch):

  https://github.com/freedreno/kernel-msm/commits/ifc6410-drm-blue-flash
  git://github.com/freedreno/kernel-msm.git ifc6410-drm-blue-flash

or if you just want to give it a quick try, I've put a pre-built
boot-img for ifc6410 here:

  http://people.freedesktop.org/~robclark/f20/ifc6410-boot-blue-flash.img

Since others were seeing the issue more than I was, I'd really
appreciate some testing, in particular by anyone was seeing this
before.  Please let me know if it fixes some or all of the issues, if
there are any regressions, etc.

BR,
-R