[Intel-gfx] [PATCH] Defined NM doesn't work on KBL and uses automatic N/M.

[Quanxian Wang]

According to the bspec, when set N/M, should disable
and enable transcoder which attaching DP audio. However
with that implementation will affect performance more.

But with current implementation, KBL could not work with defined N/M.
By default, KBL will use automatic N/M.

Signed-off-by: Quanxian Wang <quanxian.wang at intel.com>
Reviewed-by: Libin Yang <libin.yang at intel.com>
Reviewed-by: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/i915/intel_audio.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c
index d805b6e..ba4994e 100644
--- a/drivers/gpu/drm/i915/intel_audio.c
+++ b/drivers/gpu/drm/i915/intel_audio.c
@@ -289,6 +289,10 @@ hsw_dp_audio_config_update(struct intel_crtc *intel_crtc, enum port port,
 	enum pipe pipe = intel_crtc->pipe;
 	u32 tmp;
 
+	/* It doesn't work on KBL and uses automatic N/M. */
+	if (IS_KABYLAKE(dev_priv))
+		nm = NULL;
+
 	if (nm)
 		DRM_DEBUG_KMS("using Maud %u, Naud %u\n", nm->m, nm->n);
 	else
-- 
2.5.0