Bug#884061: (no subject)

[Nick Smallbone <nick@smallbone.se>]

I get this too after upgrading from 4.9.30-2+deb9u5 to 4.9.65-3.
Same dmesg error as Vagrant, together with either crazy flickering
or a hard crash. It happens usually about 30 seconds after starting X.

I tried using "git bisect" on the upstream linux-stable repository.
It points the finger at the following commit:

  7de694782cbe7840f2c0de6f1e70f41fc1b8b6e8 is the first bad commit
  commit 7de694782cbe7840f2c0de6f1e70f41fc1b8b6e8
  Author: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
  Date:   Thu Oct 19 17:13:40 2017 +0200
  
      drm/i915: Do not rely on wm preservation for ILK watermarks
      
      commit 8777b927b92cf5b6c29f9f9d3c737addea9ac8a7 upstream.
      
      The original intent was to preserve watermarks as much as possible
      in intel_pipe_wm.raw_wm, and put the validated ones in intel_pipe_wm.wm.
      
      It seems this approach is insufficient and we don't always preserve
      the raw watermarks, so just use the atomic iterator we're already using
      to get a const pointer to all bound planes on the crtc.
      
      Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102373
      Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
      Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
      Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
      Link: https://patchwork.freedesktop.org/patch/msgid/20171019151341.4579-1-maarten.lankhorst@linux.intel.com
      (cherry picked from commit 28283f4f359cd7cfa9e65457bb98c507a2cd0cd0)
      Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
      Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  
  :040000 040000 072d8db147e7c6feb397661767c67acc543fc7e1 c73d489829736f47f7186bbde766887e5a88b130 M	drivers

Indeed, using this commit provokes the error, while the parent commit
(b35783871190a8fcf31c2216638b92bcb2bf152e) does not (at least for me).

Nick