1. 04 Jan, 2016 1 commit
  2. 21 Dec, 2015 1 commit
    • Matt Roper's avatar
      drm/fb-helper: Use proper plane mask for fb cleanup · 7118fd9b
      Matt Roper authored
      pan_display_atomic() calls drm_atomic_clean_old_fb() to sanitize the
      legacy FB fields (plane->fb and plane->old_fb).  However it was building
      the plane mask to pass to this function incorrectly (the bitwise OR was
      using plane indices rather than plane masks).  The end result was that
      sometimes the legacy pointers would become out of sync with the atomic
      pointers.  If another operation tried to re-set the same FB onto the
      plane, we might end up with the pointers back in sync, but improper
      reference counts, which would eventually lead to system crashes when we
      accessed a pointer to a prematurely-destroyed FB.
      
      The cause here was a very subtle bug introduced in commit:
      
              commit 07d3bad6
              Author: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
              Date:   Wed Nov 11 11:29:11 2015 +0100
      
                  drm/core: Fix old_fb handling in pan_display_atomic.
      
      I found the crashes were most easily reproduced (on i915 at least) by
      starting X and then VT switching to a VT that wasn't running a console
      instance...the sequence of vt/fbcon entries that happen in that case
      trigger a reference count mismatch and crash the system.
      
      Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
      Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
      Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93313Signed-off-by: default avatarMatt Roper <matthew.d.roper@intel.com>
      Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      7118fd9b
  3. 15 Dec, 2015 38 commits