drm/i915: Pull GAMMA_MODE write out from haswell_load_luts()

For bdw+ let's move the GAMMA_MODE write for the legacy LUT
mode into the .load_luts() funciton directly, rather than
relying on haswell_load_luts(). We'll be getting rid of
haswell_load_luts() entirely soon, and it's anyway cleaner
to have the GAMMA_MODE write in a single place.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190205160848.24662-5-ville.syrjala@linux.intel.comReviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

drivers/gpu/drm/i915/intel_color.c

@@ -473,21 +473,20 @@ static void broadwell_load_luts(const struct intel_crtc_state *crtc_state)
 	enum pipe pipe = crtc->pipe;
 
 	if (crtc_state_is_legacy_gamma(crtc_state)) {
-		haswell_load_luts(crtc_state);
-		return;
-	}
-
+		i9xx_load_luts(crtc_state);
+	} else {
 		bdw_load_degamma_lut(crtc_state);
 		bdw_load_gamma_lut(crtc_state,
 				   INTEL_INFO(dev_priv)->color.degamma_lut_size);
 
-	I915_WRITE(GAMMA_MODE(pipe), crtc_state->gamma_mode);
-
 		/*
 		 * Reset the index, otherwise it prevents the legacy palette to be
 		 * written properly.
 		 */
 		I915_WRITE(PREC_PAL_INDEX(pipe), 0);
+	}
+
+	I915_WRITE(GAMMA_MODE(pipe), crtc_state->gamma_mode);
 }
 
 static void glk_load_degamma_lut(const struct intel_crtc_state *crtc_state)
@@ -530,12 +529,17 @@ static void glk_load_luts(const struct intel_crtc_state *crtc_state)
 	glk_load_degamma_lut(crtc_state);
 
 	if (crtc_state_is_legacy_gamma(crtc_state)) {
-		haswell_load_luts(crtc_state);
-		return;
-	}
-
+		i9xx_load_luts(crtc_state);
+	} else {
 		bdw_load_gamma_lut(crtc_state, 0);
 
+		/*
+		 * Reset the index, otherwise it prevents the legacy palette to be
+		 * written properly.
+		 */
+		I915_WRITE(PREC_PAL_INDEX(pipe), 0);
+	}
+
 	I915_WRITE(GAMMA_MODE(pipe), crtc_state->gamma_mode);
 }