intelhdmi - dont power off HDA link

For codecs without EPSS support (G45/IbexPeak), the hotplug event will
be lost if the HDA is powered off during the time. After that the pin
presence detection verb returns inaccurate info.

So always power-on HDA link for !EPSS codecs.

KarL offers the fact and Takashi recommends to flag hda_bus. Thanks!
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/hda_codec.h

@@ -639,6 +639,7 @@ struct hda_bus {
 	unsigned int rirb_error:1;	/* error in codec communication */
 	unsigned int response_reset:1;	/* controller was reset */
 	unsigned int in_reset:1;	/* during reset operation */
+	unsigned int power_keep_link_on:1; /* don't power off HDA link */
 };
 
 /*

sound/pci/hda/hda_intel.c

@@ -2082,7 +2082,8 @@ static void azx_power_notify(struct hda_bus *bus)
 	}
 	if (power_on)
 		azx_init_chip(chip);
-	else if (chip->running && power_save_controller)
+	else if (chip->running && power_save_controller &&
+		 !bus->power_keep_link_on)
 		azx_stop_chip(chip);
 }
 #endif /* CONFIG_SND_HDA_POWER_SAVE */

sound/pci/hda/patch_intelhdmi.c

@@ -391,6 +391,17 @@ static int intel_hdmi_parse_codec(struct hda_codec *codec)
 		}
 	}
 
+	/*
+	 * G45/IbexPeak don't support EPSS: the unsolicited pin hot plug event
+	 * can be lost and presence sense verb will become inaccurate if the
+	 * HDA link is powered off at hot plug or hw initialization time.
+	 */
+#ifdef CONFIG_SND_HDA_POWER_SAVE
+	if (!(snd_hda_param_read(codec, codec->afg, AC_PAR_POWER_STATE) &
+	      AC_PWRST_EPSS))
+		codec->bus->power_keep_link_on = 1;
+#endif
+
 	return 0;
 }