drm/i915/ddi: Fix eDP VDD handling during booting and suspend/resume

The driver's VDD on/off logic assumes that whenever the VDD is on we
also hold an AUX power domain reference. Since BIOS can leave the VDD on
during booting and resuming and on DDI platforms we won't take a
corresponding power reference, the above assumption won't hold on those
platforms and an eventual delayed VDD off work will do an extraneous AUX
power domain put resulting in a refcount underflow. Fix this the same
way we did this for non-DDI DP encoders:

commit 6d93c0c4 ("drm/i915: fix VDD state tracking after system
resume")

At the same time call the DP encoder suspend handler the same way as the
non-DDI DP encoders do to flush any pending VDD off work. Leaving the
work running may cause a HW access where we don't expect this (at a point
where power domains are suspended already).

While at it remove an unnecessary function call indirection.

This fixed for me AUX refcount underflow problems on BXT during
suspend/resume.

CC: Ville Syrjälä <ville.syrjala@linux.intel.com>
CC: stable@vger.kernel.org
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1460963062-13211-4-git-send-email-imre.deak@intel.com

drivers/gpu/drm/i915/intel_ddi.c

@@ -2206,12 +2206,6 @@ void intel_ddi_get_config(struct intel_encoder *encoder,
 	intel_ddi_clock_get(encoder, pipe_config);
 }
 
-static void intel_ddi_destroy(struct drm_encoder *encoder)
-{
-	/* HDMI has nothing special to destroy, so we can go with this. */
-	intel_dp_encoder_destroy(encoder);
-}
-
 static bool intel_ddi_compute_config(struct intel_encoder *encoder,
 				     struct intel_crtc_state *pipe_config)
 {
@@ -2230,7 +2224,8 @@ static bool intel_ddi_compute_config(struct intel_encoder *encoder,
 }
 
 static const struct drm_encoder_funcs intel_ddi_funcs = {
-	.destroy = intel_ddi_destroy,
+	.reset = intel_dp_encoder_reset,
+	.destroy = intel_dp_encoder_destroy,
 };
 
 static struct intel_connector *
@@ -2329,6 +2324,7 @@ void intel_ddi_init(struct drm_device *dev, enum port port)
 	intel_encoder->post_disable = intel_ddi_post_disable;
 	intel_encoder->get_hw_state = intel_ddi_get_hw_state;
 	intel_encoder->get_config = intel_ddi_get_config;
+	intel_encoder->suspend = intel_dp_encoder_suspend;
 
 	intel_dig_port->port = port;
 	intel_dig_port->saved_port_bits = I915_READ(DDI_BUF_CTL(port)) &

drivers/gpu/drm/i915/intel_dp.c

@@ -4889,7 +4889,7 @@ void intel_dp_encoder_destroy(struct drm_encoder *encoder)
 	kfree(intel_dig_port);
 }
 
-static void intel_dp_encoder_suspend(struct intel_encoder *intel_encoder)
+void intel_dp_encoder_suspend(struct intel_encoder *intel_encoder)
 {
 	struct intel_dp *intel_dp = enc_to_intel_dp(&intel_encoder->base);
 
@@ -4931,7 +4931,7 @@ static void intel_edp_panel_vdd_sanitize(struct intel_dp *intel_dp)
 	edp_panel_vdd_schedule_off(intel_dp);
 }
 
-static void intel_dp_encoder_reset(struct drm_encoder *encoder)
+void intel_dp_encoder_reset(struct drm_encoder *encoder)
 {
 	struct intel_dp *intel_dp;
 

drivers/gpu/drm/i915/intel_drv.h

@@ -1285,6 +1285,8 @@ void intel_dp_set_link_params(struct intel_dp *intel_dp,
 void intel_dp_start_link_train(struct intel_dp *intel_dp);
 void intel_dp_stop_link_train(struct intel_dp *intel_dp);
 void intel_dp_sink_dpms(struct intel_dp *intel_dp, int mode);
+void intel_dp_encoder_reset(struct drm_encoder *encoder);
+void intel_dp_encoder_suspend(struct intel_encoder *intel_encoder);
 void intel_dp_encoder_destroy(struct drm_encoder *encoder);
 int intel_dp_sink_crc(struct intel_dp *intel_dp, u8 *crc);
 bool intel_dp_compute_config(struct intel_encoder *encoder,