[PATCH v2 1/2] media: uvcvideo: Fix deferred probing error

[Ricardo Ribalda]

uvc_gpio_parse() can return -EPROBE_DEFER when the GPIOs it depends on
have not yet been probed. This return code should be propagated to the
caller of uvc_probe() to ensure that probing is retried when the required
GPIOs become available.

Currently, this error code is incorrectly converted to -ENODEV,
causing some internal cameras to be ignored.

This commit fixes this issue by propagating the -EPROBE_DEFER error.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 2886477ff987 ("media: uvcvideo: Implement UVC_EXT_GPIO_UNIT")
Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
---
 drivers/media/usb/uvc/uvc_driver.c | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index deadbcea5e22..e966bdb9239f 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -2231,13 +2231,16 @@ static int uvc_probe(struct usb_interface *intf,
 #endif
 
 	/* Parse the Video Class control descriptor. */
-	if (uvc_parse_control(dev) < 0) {
+	ret = uvc_parse_control(dev);
+	if (ret < 0) {
+		ret = -ENODEV;
 		uvc_dbg(dev, PROBE, "Unable to parse UVC descriptors\n");
 		goto error;
 	}
 
 	/* Parse the associated GPIOs. */
-	if (uvc_gpio_parse(dev) < 0) {
+	ret = uvc_gpio_parse(dev);
+	if (ret < 0) {
 		uvc_dbg(dev, PROBE, "Unable to parse UVC GPIOs\n");
 		goto error;
 	}
@@ -2263,24 +2266,32 @@ static int uvc_probe(struct usb_interface *intf,
 	}
 
 	/* Register the V4L2 device. */
-	if (v4l2_device_register(&intf->dev, &dev->vdev) < 0)
+	ret = v4l2_device_register(&intf->dev, &dev->vdev);
+	if (ret < 0)
 		goto error;
 
 	/* Scan the device for video chains. */
-	if (uvc_scan_device(dev) < 0)
+	if (uvc_scan_device(dev) < 0) {
+		ret = -ENODEV;
 		goto error;
+	}
 
 	/* Initialize controls. */
-	if (uvc_ctrl_init_device(dev) < 0)
+	if (uvc_ctrl_init_device(dev) < 0) {
+		ret = -ENODEV;
 		goto error;
+	}
 
 	/* Register video device nodes. */
-	if (uvc_register_chains(dev) < 0)
+	if (uvc_register_chains(dev) < 0) {
+		ret = -ENODEV;
 		goto error;
+	}
 
 #ifdef CONFIG_MEDIA_CONTROLLER
 	/* Register the media device node */
-	if (media_device_register(&dev->mdev) < 0)
+	ret = media_device_register(&dev->mdev);
+	if (ret < 0)
 		goto error;
 #endif
 	/* Save our data pointer in the interface data. */
@@ -2314,7 +2325,7 @@ static int uvc_probe(struct usb_interface *intf,
 error:
 	uvc_unregister_video(dev);
 	kref_put(&dev->ref, uvc_delete);
-	return -ENODEV;
+	return ret;
 }
 
 static void uvc_disconnect(struct usb_interface *intf)

-- 
2.48.1.711.g2feabab25a-goog