drm/i915: Allow user modes to exceed DVI 165MHz limit

drm/i915: Allow user modes to exceed DVI 165MHz limit

commit 40478455fefdc0bde24ae872c3f88d58a1b0e435 upstream.

In commit
 commit 6375b768a9850b6154478993e5fb566fa4614a9c
 Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
 Date:   Mon Mar 3 11:33:36 2014 +0200

    drm/i915: Reject >165MHz modes w/ DVI monitors

the driver started to filter out display modes which exceed the
single-link DVI 165Mz dotclock limits when the monitor doesn't report
itself as being HDMI compliant. The intent was to filter out all
EDID derived modes that require dual-link DVI to operate since we
don't support dual-link.

However the patch went a bit too far and also causes the driver to reject
such modes even when specified by the user. Normally we don't check the
sink limitations when setting a mode from the user. This allows the user
to specify any mode whether the sink reports to support it or not. This
can be useful since often the sinks support more modes than they report
in the EDID.

So relax the checks a bit, and apply the single-link DVI dotclock limit
only when filtering the mode list, and ignore the limit when setting
a user specified mode.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=72961
Tested-by: Nicholas Vinson <nvinson@comcast.net>
Reviewed-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>