drm/i915: DisplayPort hot remove notification to audio driver

commit 832afda6a7d7235ef0e09f4ec46736861540da6d upstream.

On DP monitor hot remove, clear DP_AUDIO_OUTPUT_ENABLE accordingly,
so that the audio driver will receive hot plug events and take action
to refresh its device state and ELD contents.

Note that the DP_AUDIO_OUTPUT_ENABLE bit may be enabled or disabled
only when the link training is complete and set to "Normal".

Tested OK for both hot plug/remove and DPMS on/off.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 14264a8..bf9fea9 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1554,6 +1554,7 @@
 			intel_wait_for_vblank(dev, to_intel_crtc(crtc)->pipe);
 	}
 
+	DP &= ~DP_AUDIO_OUTPUT_ENABLE;
 	I915_WRITE(intel_dp->output_reg, DP & ~DP_PORT_EN);
 	POSTING_READ(intel_dp->output_reg);
 }