[EXT] Re: [PATCH] libcamera: device_enumerator: exclude uvcvideo device when enumerate

[Anle Pan]

Hi Jacopo,

    It is the code added by our own project for debug that causes the crash. Not related to libcamera, please omit the patch. Thanks.

Best Regards
Anle Pan

-----Original Message-----
From: Jacopo Mondi <jacopo.mondi at ideasonboard.com> 
Sent: 2024年3月26日 17:03
To: Anle Pan <anle.pan at nxp.com>
Cc: libcamera-devel at lists.libcamera.org; Hui Fang <hui.fang at nxp.com>
Subject: [EXT] Re: [PATCH] libcamera: device_enumerator: exclude uvcvideo device when enumerate

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Hi Anle

On Tue, Mar 26, 2024 at 05:38:04PM +0900, Anle Pan wrote:
> Camera service startup crash when camera and usb camera are connected 
> at the same time, service will always reboot due to the null pointer 
> in populateEntities.

This is weird, libcamera has been used with uvcvideo devices since the very beginning. As far as I understand, this is not related to Android or its CameraService, right ? Just loading the library fails ?

>
> In this case, a UVC device was used to populate the related entities, 
> pads and links, which was not reasonable.

Not a UVC expert, but why this is not reasonable ? uvc devices have a media graph with entities, links and pads like every other device, don't they ?

>
> To fix the issue, ensure the media node is not a "uvcvideo" device 
> when enumerate before createDevice.

So this is disabling uvc support in libcamera completely, preventing uvcvideo devices from being enumerated ?

What about uvcvideo users ? :)

>
> Change-Id: I656a542e83449df287d34a4e358ae2e26e784f17
> Signed-off-by: Anle Pan <anle.pan at nxp.com>
> ---
>  src/libcamera/device_enumerator_sysfs.cpp | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
>
> diff --git a/src/libcamera/device_enumerator_sysfs.cpp 
> b/src/libcamera/device_enumerator_sysfs.cpp
> index 9979d68a..224ec8c8 100644
> --- a/src/libcamera/device_enumerator_sysfs.cpp
> +++ b/src/libcamera/device_enumerator_sysfs.cpp
> @@ -73,6 +73,27 @@ int DeviceEnumeratorSysfs::enumerate()
>                       continue;
>               }
>
> +             /* Check that the device node not a uvcvideo. */
> +             struct media_device_info devinfo;
> +             int fd = open(devnode.c_str(), O_RDWR | O_CLOEXEC);
> +             if (fd < 0) {
> +                     LOG(DeviceEnumerator, Warning)
> +                             << "Failed to open media device:" + devnode
> +                             << " (" << strerror(errno) << "), skipping";
> +                     continue;
> +             }
> +             int retval = ioctl(fd, MEDIA_IOC_DEVICE_INFO, &devinfo);
> +             close(fd);
> +             if (retval != 0) {
> +                     LOG(DeviceEnumerator, Warning)
> +                             << "Failed to get info from device:" + devnode
> +                             << " (" << strerror(errno) << "), skipping";
> +                     continue;
> +             }
> +             if (strstr("uvcvideo", devinfo.driver)) {
> +                     continue;
> +             }
> +
>               std::unique_ptr<MediaDevice> media = createDevice(devnode);
>               if (!media)
>                       continue;
> --
> 2.34.1
>