drm/i915: Skip modifying PCH DREF if not changing clock sources
authorChris Wilson <chris@chris-wilson.co.uk>
Tue, 26 Mar 2013 23:33:04 +0000 (16:33 -0700)
committerDaniel Vetter <daniel.vetter@ffwll.ch>
Tue, 2 Apr 2013 18:25:34 +0000 (20:25 +0200)
commit74cfd7ac5e1119ec3275d769ed9e27bcd97cf896
treeae085468d69dce81d81a5eebe801b8e01f347001
parent31ad8ec6a6145f9ac978a112801dbde33d44b9d1
drm/i915: Skip modifying PCH DREF if not changing clock sources

Modifying the clock sources (via the DREF control on the PCH) is a slow
multi-stage process as we need to let the clocks stabilise between each
stage. If we are not actually changing the clock sources, then we can
return early.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
[danvet: Appease checkpatch by deleting a space after a ~]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drivers/gpu/drm/i915/intel_display.c