ALSA: hda: Intel: enable automatic runtime pm for HDMI codecs by default

Enable runtime PM of the HDMI audio codec on the latest Intel platforms.
So the HD-A controller or HDMI codec can suspend when idle timeout by
default and release the GFX power well.
The patch influences HSW/BDW/BYT/BSW/SKL. Eariler platforms and third
party analog codecs will not be influenced.
Signed-off-by: Lu, Han <han.lu@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/hda_codec.c

@@ -3496,6 +3496,9 @@ static void codec_set_power_save(struct hda_codec *codec, int delay)
 {
 	struct device *dev = hda_codec_dev(codec);
 
+	if (delay == 0 && codec->auto_runtime_pm)
+		delay = 3000;
+
 	if (delay > 0) {
 		pm_runtime_set_autosuspend_delay(dev, delay);
 		pm_runtime_use_autosuspend(dev);

sound/pci/hda/hda_codec.h

@@ -251,6 +251,7 @@ struct hda_codec {
 	unsigned int dp_mst:1; /* support DP1.2 Multi-stream transport */
 	unsigned int dump_coef:1; /* dump processing coefs in codec proc file */
 	unsigned int power_save_node:1; /* advanced PM for each widget */
+	unsigned int auto_runtime_pm:1; /* enable automatic codec runtime pm */
 #ifdef CONFIG_PM
 	unsigned long power_on_acct;
 	unsigned long power_off_acct;

sound/pci/hda/patch_hdmi.c

@@ -2356,6 +2356,10 @@ static int patch_generic_hdmi(struct hda_codec *codec)
 		codec->dp_mst = true;
 	}
 
+	/* Enable runtime pm for HDMI audio codec of HSW/BDW/SKL/BYT/BSW */
+	if (is_haswell_plus(codec) || is_valleyview_plus(codec))
+		codec->auto_runtime_pm = 1;
+
 	generic_hdmi_init_per_pins(codec);
 
 	init_channel_allocations();