drm/i915: take display port power domain in DP HPD handler

Ville noticed that we can call ibx_digital_port_connected() which accesses
the HW without holding any power well/runtime pm reference. Fix this by
holding a display port power domain reference around the whole hpd_pulse
handler.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Cc: stable@vger.kernel.org (3.16+)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

1 files changed, 14 insertions, 5 deletions

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index ee3942f0b068..a520188e6d97 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4037,15 +4037,21 @@ bool
 intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
 {
         struct intel_dp *intel_dp = &intel_dig_port->dp;
+        struct intel_encoder *intel_encoder = &intel_dig_port->base;
         struct drm_device *dev = intel_dig_port->base.base.dev;
         struct drm_i915_private *dev_priv = dev->dev_private;
-        int ret;
+        enum intel_display_power_domain power_domain;
+        bool ret = true;
+
         if (intel_dig_port->base.type != INTEL_OUTPUT_EDP)
                 intel_dig_port->base.type = INTEL_OUTPUT_DISPLAYPORT;
 
         DRM_DEBUG_KMS("got hpd irq on port %d - %s\n", intel_dig_port->port,
                       long_hpd ? "long" : "short");
 
+        power_domain = intel_display_port_power_domain(intel_encoder);
+        intel_display_power_get(dev_priv, power_domain);
+
         if (long_hpd) {
                 if (!ibx_digital_port_connected(dev_priv, intel_dig_port))
                         goto mst_fail;
@@ -4061,8 +4067,7 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
 
         } else {
                 if (intel_dp->is_mst) {
-                        ret = intel_dp_check_mst_status(intel_dp);
-                        if (ret == -EINVAL)
+                        if (intel_dp_check_mst_status(intel_dp) == -EINVAL)
                                 goto mst_fail;
                 }
 
@@ -4076,7 +4081,8 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
                         drm_modeset_unlock(&dev->mode_config.connection_mutex);
                 }
         }
-        return false;
+        ret = false;
+        goto put_power;
 mst_fail:
         /* if we were in MST mode, and device is not there get out of MST mode */
         if (intel_dp->is_mst) {
@@ -4084,7 +4090,10 @@ mst_fail:
                 intel_dp->is_mst = false;
                 drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst_mgr, intel_dp->is_mst);
         }
-        return true;
+put_power:
+        intel_display_power_put(dev_priv, power_domain);
+
+        return ret;
 }
 
 /* Return which DP Port should be selected for Transcoder DP control */