From: "Lu, Han" han.lu@intel.com

For SKL we added a commit 632f3ab95fe2 ("drm/i915/audio: add codec wakeup override enabled/disable callback"), in order to enable codec wakeup override signal, to allow re-enumeration of the controller on SKL after resume from low power state. In SKL, HDMI/DP codec and PCH HD Audio Controller are in different power wells, so it's necessary to reset display audio codecs when power well on, otherwise display audio codecs will disappear when resume from low power state. Reset steps when power on: enable codec wakeup -> azx_init_chip() -> disable codec wakeup The work around is applicable for chips with power well design similar to SKL, like BXT.

v2: add explanation

v3: use gen check instead of list all available chips

Signed-off-by: Lu, Han han.lu@intel.com

diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c index 63d4706..4c01018 100644 --- a/drivers/gpu/drm/i915/intel_audio.c +++ b/drivers/gpu/drm/i915/intel_audio.c @@ -591,7 +591,12 @@ static void i915_audio_component_codec_wake_override(struct device *dev, struct drm_i915_private *dev_priv = dev_to_i915(dev); u32 tmp;

- if (!IS_SKYLAKE(dev_priv) && !IS_KABYLAKE(dev_priv)) + /* + * The patch is only applicable to chips that HDMI/DP codecs and PCH + * HD Audio Controller are in different power wells, such as SKL, + * BXT and KBL. + */ + if (INTEL_INFO(dev_priv)->gen < 9) return;

/*