Just like we do for the other encoders. This should fix some WARNs
when running pm_rpm on SNB.
Testcase: igt/pm_rpm
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=80463
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
        struct drm_device *dev = encoder->base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_lvds_encoder *lvds_encoder = to_lvds_encoder(&encoder->base);
+       enum intel_display_power_domain power_domain;
        u32 tmp;
 
+       power_domain = intel_display_port_power_domain(encoder);
+       if (!intel_display_power_enabled(dev_priv, power_domain))
+               return false;
+
        tmp = I915_READ(lvds_encoder->reg);
 
        if (!(tmp & LVDS_PORT_EN))