drm/i915: Wait for power cycle delay after turning off DSI panel power

The power cycle delay starts _after_ turning off the panel power. Do the
msleep after frobbing the pmic panel power gpio.

Also toss in a FIXME about optimizing away needless waits.

Cc: Shobhit Kumar <shobhit.kumar@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Fixes: fc45e8219907 ("drm/i915: Use the CRC gpio for panel enable/disable")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1460996271-29795-1-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Shobhit Kumar <shobhit.kumar@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/intel_dsi.c

@@ -688,11 +688,16 @@ static void intel_dsi_post_disable(struct intel_encoder *encoder)
 	drm_panel_unprepare(intel_dsi->panel);
 
 	msleep(intel_dsi->panel_off_delay);
-	msleep(intel_dsi->panel_pwr_cycle_delay);
 
 	/* Panel Disable over CRC PMIC */
 	if (intel_dsi->gpio_panel)
 		gpiod_set_value_cansleep(intel_dsi->gpio_panel, 0);
+
+	/*
+	 * FIXME As we do with eDP, just make a note of the time here
+	 * and perform the wait before the next panel power on.
+	 */
+	msleep(intel_dsi->panel_pwr_cycle_delay);
 }
 
 static bool intel_dsi_get_hw_state(struct intel_encoder *encoder,