drm/i915: Move the SKL DPLL0 VCO computation into intel_dp_compute_config()

Shared plls won't get assigned until the .compute_clocks() hook gets
called, which happens from the crtc .atomic_check hook. That's too late
as the cdclk computation has already happened. So let's move the DPLL0
VCO computation into intel_dp_compute_config() so that it's done when
the cdclk computation happens. Also only do it for eDP since we only
pick DPLL0 for eDP.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463172100-24715-4-git-send-email-ville.syrjala@linux.intel.comReviewed-by: Imre Deak <imre.deak@intel.com>

drivers/gpu/drm/i915/intel_dp.c

@@ -1578,6 +1578,27 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 				&pipe_config->dp_m2_n2);
 	}
 
+	/*
+	 * DPLL0 VCO may need to be adjusted to get the correct
+	 * clock for eDP. This will affect cdclk as well.
+	 */
+	if (is_edp(intel_dp) &&
+	    (IS_SKYLAKE(dev_priv) || IS_KABYLAKE(dev_priv))) {
+		int vco;
+
+		switch (pipe_config->port_clock / 2) {
+		case 108000:
+		case 216000:
+			vco = 8640;
+			break;
+		default:
+			vco = 8100;
+			break;
+		}
+
+		to_intel_atomic_state(pipe_config->base.state)->cdclk_pll_vco = vco;
+	}
+
 	if (!HAS_DDI(dev))
 		intel_dp_set_clock(encoder, pipe_config);
 

drivers/gpu/drm/i915/intel_dpll_mgr.c

@@ -1194,7 +1194,6 @@ skl_get_dpll(struct intel_crtc *crtc, struct intel_crtc_state *crtc_state,
 	struct intel_shared_dpll *pll;
 	uint32_t ctrl1, cfgcr1, cfgcr2;
 	int clock = crtc_state->port_clock;
-	uint32_t vco = 8100;
 
 	/*
 	 * See comment in intel_dpll_hw_state to understand why we always use 0
@@ -1239,15 +1238,12 @@ skl_get_dpll(struct intel_crtc *crtc, struct intel_crtc_state *crtc_state,
 			break;
 		case 108000:
 			ctrl1 |= DPLL_CTRL1_LINK_RATE(DPLL_CTRL1_LINK_RATE_1080, 0);
-			vco = 8640;
 			break;
 		case 216000:
 			ctrl1 |= DPLL_CTRL1_LINK_RATE(DPLL_CTRL1_LINK_RATE_2160, 0);
-			vco = 8640;
 			break;
 		}
 
-		to_intel_atomic_state(crtc_state->base.state)->cdclk_pll_vco = vco;
 		cfgcr1 = cfgcr2 = 0;
 	} else {
 		return NULL;