Some applications need to check if there is an input device on the camera
before proceeding to the next step. When there is no input device,
the application will report an error.
Create input device for all uvc devices with status endpoints.
and only when bTriggerSupport and bTriggerUsage are one are
allowed to report camera button.

Fixes: 3bc22dc66a4f ("media: uvcvideo: Only create input devs if hw supports it")
Signed-off-by: chenchangcheng <ccc194101@163.com>
---
 drivers/media/usb/uvc/uvc_status.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_status.c b/drivers/media/usb/uvc/uvc_status.c
index a78a88c710e2..177640c6a813 100644
--- a/drivers/media/usb/uvc/uvc_status.c
+++ b/drivers/media/usb/uvc/uvc_status.c
@@ -44,9 +44,6 @@ static int uvc_input_init(struct uvc_device *dev)
 	struct input_dev *input;
 	int ret;
 
-	if (!uvc_input_has_button(dev))
-		return 0;
-
 	input = input_allocate_device();
 	if (input == NULL)
 		return -ENOMEM;
@@ -110,10 +107,12 @@ static void uvc_event_streaming(struct uvc_device *dev,
 		if (len <= offsetof(struct uvc_status, streaming))
 			return;
 
-		uvc_dbg(dev, STATUS, "Button (intf %u) %s len %d\n",
-			status->bOriginator,
-			status->streaming.button ? "pressed" : "released", len);
-		uvc_input_report_key(dev, KEY_CAMERA, status->streaming.button);
+		if (uvc_input_has_button(dev)) {
+			uvc_dbg(dev, STATUS, "Button (intf %u) %s len %d\n",
+				status->bOriginator,
+				status->streaming.button ? "pressed" : "released", len);
+			uvc_input_report_key(dev, KEY_CAMERA, status->streaming.button);
+		}
 	} else {
 		uvc_dbg(dev, STATUS, "Stream %u error event %02x len %d\n",
 			status->bOriginator, status->bEvent, len);

base-commit: ff7afaeca1a15fbeaa2c4795ee806c0667bd77b2
-- 
2.25.1

Hello,

On Fri, Nov 08, 2024 at 09:56:58AM +0800, chenchangcheng wrote:
> Some applications need to check if there is an input device on the camera
> before proceeding to the next step. When there is no input device,
> the application will report an error.

As Mauro previously mentioned, this seems to be an application issue,
not a kernel issue. You should fix the application.

> Create input device for all uvc devices with status endpoints.
> and only when bTriggerSupport and bTriggerUsage are one are
> allowed to report camera button.
> 
> Fixes: 3bc22dc66a4f ("media: uvcvideo: Only create input devs if hw supports it")
> Signed-off-by: chenchangcheng <ccc194101@163.com>
> ---
>  drivers/media/usb/uvc/uvc_status.c | 13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/media/usb/uvc/uvc_status.c b/drivers/media/usb/uvc/uvc_status.c
> index a78a88c710e2..177640c6a813 100644
> --- a/drivers/media/usb/uvc/uvc_status.c
> +++ b/drivers/media/usb/uvc/uvc_status.c
> @@ -44,9 +44,6 @@ static int uvc_input_init(struct uvc_device *dev)
>  	struct input_dev *input;
>  	int ret;
>  
> -	if (!uvc_input_has_button(dev))
> -		return 0;
> -
>  	input = input_allocate_device();
>  	if (input == NULL)
>  		return -ENOMEM;
> @@ -110,10 +107,12 @@ static void uvc_event_streaming(struct uvc_device *dev,
>  		if (len <= offsetof(struct uvc_status, streaming))
>  			return;
>  
> -		uvc_dbg(dev, STATUS, "Button (intf %u) %s len %d\n",
> -			status->bOriginator,
> -			status->streaming.button ? "pressed" : "released", len);
> -		uvc_input_report_key(dev, KEY_CAMERA, status->streaming.button);
> +		if (uvc_input_has_button(dev)) {
> +			uvc_dbg(dev, STATUS, "Button (intf %u) %s len %d\n",
> +				status->bOriginator,
> +				status->streaming.button ? "pressed" : "released", len);
> +			uvc_input_report_key(dev, KEY_CAMERA, status->streaming.button);
> +		}
>  	} else {
>  		uvc_dbg(dev, STATUS, "Stream %u error event %02x len %d\n",
>  			status->bOriginator, status->bEvent, len);
> 
> base-commit: ff7afaeca1a15fbeaa2c4795ee806c0667bd77b2

-- 
Regards,

Laurent Pinchart