drm/i915/lvds: Restore dithering on native modes for gen2/3

A regression introduced in bee17e5 cleared the dithering bit for native
modes on gen2/3.

Bugzilla: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/711568
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 6 insertions, 6 deletions

diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index ace8d5d30dd2..bcdba7bd5cfa 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -261,12 +261,6 @@ static bool intel_lvds_mode_fixup(struct drm_encoder *encoder,
                 return true;
         }
 
-        /* Make sure pre-965s set dither correctly */
-        if (INTEL_INFO(dev)->gen < 4) {
-                if (dev_priv->lvds_dither)
-                        pfit_control |= PANEL_8TO6_DITHER_ENABLE;
-        }
-
         /* Native modes don't need fitting */
         if (adjusted_mode->hdisplay == mode->hdisplay &&
             adjusted_mode->vdisplay == mode->vdisplay)
@@ -374,10 +368,16 @@ static bool intel_lvds_mode_fixup(struct drm_encoder *encoder,
         }
 
 out:
+        /* If not enabling scaling, be consistent and always use 0. */
         if ((pfit_control & PFIT_ENABLE) == 0) {
                 pfit_control = 0;
                 pfit_pgm_ratios = 0;
         }
+
+        /* Make sure pre-965 set dither correctly */
+        if (INTEL_INFO(dev)->gen < 4 && dev_priv->lvds_dither)
+                pfit_control |= PANEL_8TO6_DITHER_ENABLE;
+
         if (pfit_control != intel_lvds->pfit_control ||
             pfit_pgm_ratios != intel_lvds->pfit_pgm_ratios) {
                 intel_lvds->pfit_control = pfit_control;