ALSA: hda: fix a runtime pm issue in SOF when integrated GPU is disabled

In snd_hdac_device_init pm_runtime_set_active is called to
increase child_count in parent device. But when it is failed
to build connection with GPU for one case that integrated
graphic gpu is disabled, snd_hdac_ext_bus_device_exit will be
invoked to clean up a HD-audio extended codec base device. At
this time the child_count of parent is not decreased, which
makes parent device can't get suspended.

This patch calls pm_runtime_set_suspended to decrease child_count
in parent device in snd_hdac_device_exit to match with
snd_hdac_device_init. pm_runtime_set_suspended can make sure that
it will not decrease child_count if the device is already suspended.
Signed-off-by: Rander Wang <rander.wang@intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20200902154218.1440441-1-kai.vehmanen@linux.intel.comSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/hda/hdac_device.c

@@ -127,6 +127,8 @@ EXPORT_SYMBOL_GPL(snd_hdac_device_init);
 void snd_hdac_device_exit(struct hdac_device *codec)
 {
 	pm_runtime_put_noidle(&codec->dev);
+	/* keep balance of runtime PM child_count in parent device */
+	pm_runtime_set_suspended(&codec->dev);
 	snd_hdac_bus_remove_device(codec->bus, codec);
 	kfree(codec->vendor_name);
 	kfree(codec->chip_name);