drm/i915: set dither bits on eDP panels too

We really need a macro to test whether a given connector has a panel
attached rather than sprinkling HAS_PCH_SPLIT/IS_eDP/has_edp_encoder
etc all over. In the meantime, fix the bug...

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
[ickle: tidy up the duplicity in the conditionals]
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 17 insertions, 18 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 948a3608d1bd..4b23646304df 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3909,11 +3909,6 @@ static int intel_crtc_mode_set(struct drm_crtc *crtc,
                 udelay(150);
         }
 
-        if (HAS_PCH_SPLIT(dev)) {
-                pipeconf &= ~PIPECONF_DITHER_EN;
-                pipeconf &= ~PIPECONF_DITHER_TYPE_MASK;
-        }
-
         /* The LVDS pin pair needs to be on before the DPLLs are enabled.
          * This is an exception to the general rule that mode_set doesn't turn
          * things on.
@@ -3951,23 +3946,27 @@ static int intel_crtc_mode_set(struct drm_crtc *crtc,
                  * appropriately here, but we need to look more thoroughly into how
                  * panels behave in the two modes.
                  */
-                /* set the dithering flag */
-                if (IS_I965G(dev)) {
-                        if (dev_priv->lvds_dither) {
-                                if (HAS_PCH_SPLIT(dev)) {
-                                        pipeconf |= PIPECONF_DITHER_EN;
-                                        pipeconf |= PIPECONF_DITHER_TYPE_ST1;
-                                } else
-                                        lvds |= LVDS_ENABLE_DITHER;
-                        } else {
-                                if (!HAS_PCH_SPLIT(dev)) {
-                                        lvds &= ~LVDS_ENABLE_DITHER;
-                                }
-                        }
+                /* set the dithering flag on non-PCH LVDS as needed */
+                if (IS_I965G(dev) && !HAS_PCH_SPLIT(dev)) {
+                        if (dev_priv->lvds_dither)
+                                lvds |= LVDS_ENABLE_DITHER;
+                        else
+                                lvds &= ~LVDS_ENABLE_DITHER;
                 }
                 I915_WRITE(lvds_reg, lvds);
                 I915_READ(lvds_reg);
         }
+
+        /* set the dithering flag and clear for anything other than a panel. */
+        if (HAS_PCH_SPLIT(dev)) {
+                pipeconf &= ~PIPECONF_DITHER_EN;
+                pipeconf &= ~PIPECONF_DITHER_TYPE_MASK;
+                if (dev_priv->lvds_dither && (is_lvds || has_edp_encoder)) {
+                        pipeconf |= PIPECONF_DITHER_EN;
+                        pipeconf |= PIPECONF_DITHER_TYPE_ST1;
+                }
+        }
+
         if (is_dp)
                 intel_dp_set_m_n(crtc, mode, adjusted_mode);
         else if (HAS_PCH_SPLIT(dev)) {