On Sun, 23 Feb 2025 at 15:36, Laurent Pinchart
<laurent.pinchart@xxxxxxxxxxxxxxxx> wrote:
>
> Hi Ricardo,
>
> Thank you for the patch.
>
> On Wed, Jan 29, 2025 at 12:39:46PM +0000, Ricardo Ribalda wrote:
> > 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")
> > Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
> > ---
> > drivers/media/usb/uvc/uvc_driver.c | 9 ++++++---
> > 1 file changed, 6 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> > index a10d4f4d9f95..73a7f23b616c 100644
> > --- a/drivers/media/usb/uvc/uvc_driver.c
> > +++ b/drivers/media/usb/uvc/uvc_driver.c
> > @@ -2253,9 +2253,10 @@ static int uvc_probe(struct usb_interface *intf,
> > }
> >
> > /* 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;
> > + goto error_retcode;
> > }
> >
> > dev_info(&dev->udev->dev, "Found UVC %u.%02x device %s (%04x:%04x)\n",
> > @@ -2328,9 +2329,11 @@ static int uvc_probe(struct usb_interface *intf,
> > return 0;
> >
> > error:
> > + ret = -ENODEV;
> > +error_retcode:
>
> This isn't very nice. Could we instead also propagate error codes from
> other locations in the uvc_probe() function ? If you want to minimize
> changes, you can initialize ret to -ENODEV, and turn the (ret < 0) check
> for uvc_gpio_parse() to a (ret) check.
Not very nice, but easy to backport to stables. What about a follow-up
change like this:
index c93abe2367aa..8c67feca1688 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -2261,7 +2261,7 @@ static int uvc_probe(struct usb_interface *intf,
ret = uvc_gpio_parse(dev);
if (ret < 0) {
uvc_dbg(dev, PROBE, "Unable to parse UVC GPIOs\n");
- goto error_retcode;
+ goto error;
}
dev_info(&dev->udev->dev, "Found UVC %u.%02x device %s (%04x:%04x)\n",
@@ -2285,24 +2285,32 @@ 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. */
@@ -2334,8 +2342,6 @@ static int uvc_probe(struct usb_interface *intf,
return 0;
error:
- ret = -ENODEV;
-error_retcode:
uvc_unregister_video(dev);
kref_put(&dev->ref, uvc_delete);
return ret;
>
> > uvc_unregister_video(dev);
> > kref_put(&dev->ref, uvc_delete);
> > - return -ENODEV;
> > + return ret;
> > }
> >
> > static void uvc_disconnect(struct usb_interface *intf)
> >
> > ---
> > base-commit: c4b7779abc6633677e6edb79e2809f4f61fde157
> > change-id: 20250129-uvc-eprobedefer-b5ebb4db63cc
>
> --
> Regards,
>
> Laurent Pinchart
Let me know what do you think so I can send a v2 with the change
proposed by Doug.
Regards!
--
Ricardo Ribalda
