drm/i915: take a power domain reference while checking the HDMI live status

There are platforms that don't need the full GMBUS power domain (BXT)
while others do (PCH, VLV/CHV). For optimizing this we would need to add
a new power domain, but it's not clear how much we would benefit given
the short time we hold the reference. So for now let's keep things
simple.

v2:
- fix commit message, PCH won't take any redundant power resource after
this change (Ville)

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
[fix commit message in v2 (Imre)]
Link: http://patchwork.freedesktop.org/patch/msgid/1447959301-1263-2-git-send-email-imre.deak@intel.com

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index 17ced03f1b60..bdd462e7c690 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -1393,6 +1393,8 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
         DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n",
                       connector->base.id, connector->name);
 
+        intel_display_power_get(dev_priv, POWER_DOMAIN_GMBUS);
+
         while (!live_status && --retry) {
                 live_status = intel_digital_port_connected(dev_priv,
                                 hdmi_to_dig_port(intel_hdmi));
@@ -1412,6 +1414,8 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
         } else
                 status = connector_status_disconnected;
 
+        intel_display_power_put(dev_priv, POWER_DOMAIN_GMBUS);
+
         return status;
 }