drm/i915: disable powersave feature for Ironlake currently

Until we figure out the right setting for powersave features on
Ironlake, disable it for now. Also disable watermark update,
which has new registers for it on Ironlake too.

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
[anholt: Resolved against the Pineview FBC changes]
Signed-off-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/i915/intel_display.c

@@ -2586,6 +2586,9 @@ static void intel_update_watermarks(struct drm_device *dev)
 	unsigned long planea_clock = 0, planeb_clock = 0, sr_clock = 0;
 	int enabled = 0, pixel_size = 0;
 
+	if (!dev_priv->display.update_wm)
+		return;
+
 	/* Get the clock config from both planes */
 	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
 		intel_crtc = to_intel_crtc(crtc);
@@ -4126,7 +4129,9 @@ void intel_init_clock_gating(struct drm_device *dev)
 	 * Disable clock gating reported to work incorrectly according to the
 	 * specs, but enable as much else as we can.
 	 */
-	if (IS_G4X(dev)) {
+	if (IS_IGDNG(dev)) {
+		return;
+	} else if (IS_G4X(dev)) {
 		uint32_t dspclk_gate;
 		I915_WRITE(RENCLK_GATE_D1, 0);
 		I915_WRITE(RENCLK_GATE_D2, VF_UNIT_CLOCK_GATE_DISABLE |
@@ -4214,7 +4219,9 @@ static void intel_init_display(struct drm_device *dev)
 			i830_get_display_clock_speed;
 
 	/* For FIFO watermark updates */
-	if (IS_G4X(dev))
+	if (IS_IGDNG(dev))
+		dev_priv->display.update_wm = NULL;
+	else if (IS_G4X(dev))
 		dev_priv->display.update_wm = g4x_update_wm;
 	else if (IS_I965G(dev))
 		dev_priv->display.update_wm = i965_update_wm;