[Intel-gfx] [PATCH] drm/i915: Acquire audio powerwell for HD-Audio registers

[Chris Wilson]

On Haswell/Broadwell, the HD-Audio block is inside the HDMI/display
power well and so the sna-hda audio codec acquires the display power
well while it is operational. However, Skylake separates the powerwells
again, but yet we still need the audio powerwell to setup the registers.
(But then the hardware uses those registers even while powered off???)

v2: Grab both rpm wakelock and audio wakelock

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96214
Fixes: 03b135cebc47 "ALSA: hda - remove dependency on i915 power well for SKL")
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Libin Yang <libin.yang at intel.com>
Cc: Takashi Iwai <tiwai at suse.de>
Cc: Marius Vlad <marius.c.vlad at intel.com>
Tested-by: Hans de Goede <hdegoede at redhat.com>
Cc: stable at vger.kernel.org
---
 drivers/gpu/drm/i915/intel_audio.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c
index 5d5f6bc10e85..948a7a52e3f8 100644
--- a/drivers/gpu/drm/i915/intel_audio.c
+++ b/drivers/gpu/drm/i915/intel_audio.c
@@ -600,6 +600,8 @@ static void i915_audio_component_codec_wake_override(struct device *dev,
 	if (!IS_SKYLAKE(dev_priv) && !IS_KABYLAKE(dev_priv))
 		return;
 
+	i915_audio_component_get_power(dev);
+
 	/*
 	 * Enable/disable generating the codec wake signal, overriding the
 	 * internal logic to generate the codec wake to controller.
@@ -615,6 +617,8 @@ static void i915_audio_component_codec_wake_override(struct device *dev,
 		I915_WRITE(HSW_AUD_CHICKENBIT, tmp);
 		usleep_range(1000, 1500);
 	}
+
+	i915_audio_component_put_power(dev);
 }
 
 /* Get CDCLK in kHz  */
@@ -648,6 +652,7 @@ static int i915_audio_component_sync_audio_rate(struct device *dev,
 	    !IS_HASWELL(dev_priv))
 		return 0;
 
+	i915_audio_component_get_power(dev);
 	mutex_lock(&dev_priv->av_mutex);
 	/* 1. get the pipe */
 	intel_encoder = dev_priv->dig_port_map[port];
@@ -698,6 +703,7 @@ static int i915_audio_component_sync_audio_rate(struct device *dev,
 
  unlock:
 	mutex_unlock(&dev_priv->av_mutex);
+	i915_audio_component_put_power(dev);
 	return err;
 }
 
-- 
2.8.1