ASoC: SOF: Intel: fix page fault at probe if i915 init fails

The earlier commit to fix runtime PM in case i915 init fails,
introduces a possibility to hit a page fault.

snd_hdac_ext_bus_device_exit() is designed to be called from
dev.release(). Calling it outside device reference counting, is
not safe and may lead to calling the device_exit() function
twice. Additionally, as part of ext_bus_device_init(), the device
is also registered with snd_hdac_device_register(). Thus before
calling device_exit(), the device must be removed from device
hierarchy first.

Fix the issue by rolling back init actions by calling
hdac_device_unregister() and then releasing device with put_device().
This matches with existing code in hdac-ext module.

To complete the fix, add handling for the case where
hda_codec_load_module() returns -ENODEV, and clean up the hdac_ext
resources also in this case.

In future work, hdac-ext interface should be extended to allow clients
more flexibility to handle the life-cycle of individual devices, beyond
just the current snd_hdac_ext_bus_device_remove(), which removes all
devices.

BugLink: thesofproject#2646
Reported-by: Jaroslav Kysela <[email protected]>
Fixes: 6c63c95 ("ASoC: SOF: fix a runtime pm issue in SOF when HDMI codec doesn't work")
Signed-off-by: Kai Vehmanen <[email protected]>
Reviewed-by: Rander Wang <[email protected]>
Reviewed-by: Libin Yang <[email protected]>
Reviewed-by: Bard Liao <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>

sound/soc/sof/intel/hda-codec.c

@@ -153,7 +153,8 @@ static int hda_codec_probe(struct snd_sof_dev *sdev, int address,
 		if (!hdev->bus->audio_component) {
 			dev_dbg(sdev->dev,
 				"iDisp hw present but no driver\n");
-			goto error;
+			ret = -ENOENT;
+			goto out;
 		}
 		hda_priv->need_display_power = true;
 	}
@@ -170,24 +171,23 @@ static int hda_codec_probe(struct snd_sof_dev *sdev, int address,
 		 * other return codes without modification
 		 */
 		if (ret == 0)
-			goto error;
+			ret = -ENOENT;
 	}
 
-	return ret;
-
-error:
-	snd_hdac_ext_bus_device_exit(hdev);
-	return -ENOENT;
-
+out:
+	if (ret < 0) {
+		snd_hdac_device_unregister(hdev);
+		put_device(&hdev->dev);
+	}
 #else
 	hdev = devm_kzalloc(sdev->dev, sizeof(*hdev), GFP_KERNEL);
 	if (!hdev)
 		return -ENOMEM;
 
 	ret = snd_hdac_ext_bus_device_init(&hbus->core, address, hdev, HDA_DEV_ASOC);
+#endif
 
 	return ret;
-#endif
 }
 
 /* Codec initialization */