drm/i915: Retry DP aux_ch communications with a different clock after failure
authorChris Wilson <chris@chris-wilson.co.uk>
Sun, 21 Jul 2013 15:00:03 +0000 (16:00 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 13 Nov 2013 03:08:11 +0000 (12:08 +0900)
commitef4ea0912a5dd2b67353f83acd09d651650cba8f
treebc1d74b98d758efd546e1176c413159307382ece
parent141d9920e281a4597379b7f43c9c2b9fa340b22a
drm/i915: Retry DP aux_ch communications with a different clock after failure

commit bc86625a4ff7574d4d4dba79723457711eb784e0 upstream.

The w/a db makes the recommendation to both use a non-default value for
the initial clock and then to retry with an alternative clock for
Haswell with the Lakeport PCH.

"On LPT:H, use a divider value of 63 decimal (03Fh). If there is a
failure, retry at least three times with 63, then retry at least three
times with 72 decimal (048h)."

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/gpu/drm/i915/intel_dp.c