drm/i915: No need to wait for eDP power off delay if panel is on

If the panel is powered up, there's no need to delay for the 'off'
interval when turning the panel on.
Signed-off-by: Keith Packard <keithp@keithp.com>

drivers/gpu/drm/i915/intel_dp.c

@@ -869,7 +869,16 @@ static void ironlake_wait_panel_off(struct intel_dp *intel_dp)
 {
 	unsigned long	off_time;
 	unsigned long	delay;
+
 	DRM_DEBUG_KMS("Wait for panel power off time\n");
+
+	if (ironlake_edp_have_panel_power(intel_dp) ||
+	    ironlake_edp_have_panel_vdd(intel_dp))
+	{
+		DRM_DEBUG_KMS("Panel still on, no delay needed\n");
+		return;
+	}
+
 	off_time = intel_dp->panel_off_jiffies + msecs_to_jiffies(intel_dp->panel_power_down_delay);
 	if (time_after(jiffies, off_time)) {
 		DRM_DEBUG_KMS("Time already passed");