• Daniel Vetter's avatar
    drm/i915: preserve pipe A quirk in i9xx_set_pipeconf · 67c72a12
    Daniel Vetter authored
    This regression has been introduced in
    
    commit 9f11a9e4
    Author: Daniel Vetter <daniel.vetter@ffwll.ch>
    Date:   Thu Jun 13 00:54:58 2013 +0200
    
        drm/i915: set up PIPECONF explicitly for i9xx/vlv platforms
    
    Ville brough up the idea that this is just the pipe A quirk gone
    wrong.
    
    Note that after resume the bios might or might not have enabled pipe A
    already.  We have a bit of magic to make sure that on resume we set up
    a decent mode for pipe A, but I fear if I just smash pipe A to always
    on we'd enable it in a bogus state and hang the hw. Hence the
    readback.
    
    v2: Clarify the logic a bit as suggested by Chris. Also amend the
    commit message to clarify why we don't unconditionally enable the
    pipe.
    
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=66462
    References: https://lkml.org/lkml/2013/8/26/238
    Cc: Meelis Roos <mroos@ut.ee>
    Cc: Chris Wilson <chris@chris-wilson.co.uk>
    Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
    Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
    [danvet: Use |= instead of = as suggested by Chris.]
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
    67c72a12
intel_display.c 293 KB