drm/i915: Use CK505 as non-SSC source where available
authorKeith Packard <keithp@keithp.com>
Mon, 26 Sep 2011 21:29:12 +0000 (14:29 -0700)
committerKeith Packard <keithp@keithp.com>
Wed, 28 Sep 2011 21:08:06 +0000 (14:08 -0700)
commit99eb6a01e5ac6cf28aadc64e6ff346939874dfd2
tree9d91704f1196bf33b62c0355c4bab61f395eab3f
parent199e5d79f1c988a8039fa75b736a3adcdda56abc
drm/i915: Use CK505 as non-SSC source where available

When trying to use SSC on Ibex Peak without CK505, any non-SSC outputs
(like VGA or TV) get broken. So, do not use SSC on Ibex Peak unless
there is a CK505 available (as specified by the VBT).

On Cougar Point, all clocking is internal, so SSC can always be used,
and there will never be a CK505 available.

This eliminates VGA shimmer on some Ironlake machines which have a
CK505 clock source.

References: https://bugzilla.kernel.org/show_bug.cgi?id=21742
References: https://bugs.freedesktop.org/show_bug.cgi?id=38750
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
drivers/gpu/drm/i915/intel_display.c