[Intel-gfx] [PATCH v3] drm/i915/audio: fix hdmi audio noise issue

[libin.yang at intel.com]

From: Libin Yang <libin.yang at intel.com>

Some monitors will have noise or even no sound after
applying the patch 6014ac12.

In patch 6014ac12, it will reset the cts value to 0 for HDMI.
However, we need to disable Enable CTS or M Prog bit. This is
the initial setting after HW reset.

Fixes: 6014ac122ed0 ("drm/i915/audio: set proper N/M in modeset")
Signed-off-by: Libin Yang <libin.yang at intel.com>
---
 drivers/gpu/drm/i915/intel_audio.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c
index 195223d..88ed869 100644
--- a/drivers/gpu/drm/i915/intel_audio.c
+++ b/drivers/gpu/drm/i915/intel_audio.c
@@ -351,10 +351,13 @@ hsw_hdmi_audio_config_update(struct intel_crtc *intel_crtc, enum port port,
 
 	I915_WRITE(HSW_AUD_CFG(pipe), tmp);
 
+	/*
+	 * Let's disable "Enable CTS or M Prog bit"
+	 * and let HW calculate the value
+	 */
 	tmp = I915_READ(HSW_AUD_M_CTS_ENABLE(pipe));
-	tmp &= ~AUD_CONFIG_M_MASK;
+	tmp &= ~AUD_M_CTS_M_PROG_ENABLE;
 	tmp &= ~AUD_M_CTS_M_VALUE_INDEX;
-	tmp |= AUD_M_CTS_M_PROG_ENABLE;
 	I915_WRITE(HSW_AUD_M_CTS_ENABLE(pipe), tmp);
 }
 
-- 
2.7.4