linux-kernel - [PATCH 4.7 087/143] drm/i915: Acquire audio powerwell for HD-Audio registers

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Date:   Mon,  5 Sep 2016 18:44:23 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Chris Wilson <chris@...is-wilson.co.uk>,
        Libin Yang <libin.yang@...el.com>,
        Takashi Iwai <tiwai@...e.de>,
        Marius Vlad <marius.c.vlad@...el.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        Jani Nikula <jani.nikula@...el.com>
Subject: [PATCH 4.7 087/143] drm/i915: Acquire audio powerwell for HD-Audio registers

4.7-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chris Wilson <chris@...is-wilson.co.uk>

commit 3cffb0a44750726cdc1cc07399efe3cbb45e028b upstream.

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???)

Acquiring the powerwell around setting the chicken bits when setting up
the audio channel does at least silence the WARNs from touching our
registers whilst unpowered. We silence our own test cases, but maybe
there is a latent bug in using the audio channel?

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@...is-wilson.co.uk>
Cc: Libin Yang <libin.yang@...el.com>
Cc: Takashi Iwai <tiwai@...e.de>
Cc: Marius Vlad <marius.c.vlad@...el.com>
Tested-by: Hans de Goede <hdegoede@...hat.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470240540-29004-1-git-send-email-chris@chris-wilson.co.uk
Reviewed-by: Daniel Vetter <daniel.vetter@...ll.ch>
(cherry picked from commit d838a110f0b310d408ebe6b5a97e36ec27555ebf)
Signed-off-by: Jani Nikula <jani.nikula@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/gpu/drm/i915/intel_audio.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- 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_w
 	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_w
 		I915_WRITE(HSW_AUD_CHICKENBIT, tmp);
 		usleep_range(1000, 1500);
 	}
+
+	i915_audio_component_put_power(dev);
 }
 
 /* Get CDCLK in kHz  */
@@ -654,6 +658,7 @@ static int i915_audio_component_sync_aud
 	    !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];
@@ -704,6 +709,7 @@ static int i915_audio_component_sync_aud
 
  unlock:
 	mutex_unlock(&dev_priv->av_mutex);
+	i915_audio_component_put_power(dev);
 	return err;
 }