drm/i915: Ban Haswell from using RCS flips

commit 48bf5b2d upstream.

Like Ivybridge, we have reports that we get random hangs when flipping
with multiple pipes. Extend

commit 2a92d5bc
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Tue Jul 8 10:40:29 2014 +0100

    drm/i915: Disable RCS flips on Ivybridge

to also apply to Haswell.
Reported-and-tested-by: Scott Tsai <scottt.tw@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=87759Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/gpu/drm/i915/intel_display.c

@@ -9313,7 +9313,7 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc,
 
 	if (IS_VALLEYVIEW(dev)) {
 		ring = &dev_priv->ring[BCS];
-	} else if (IS_IVYBRIDGE(dev)) {
+	} else if (IS_IVYBRIDGE(dev) || IS_HASWELL(dev)) {
 		ring = &dev_priv->ring[BCS];
 	} else if (INTEL_INFO(dev)->gen >= 7) {
 		ring = obj->ring;