[libcamera-devel] [PATCH] libcamera: device_enumerator: Don't stop if one device fails

[Kieran Bingham]

On 17/02/2020 08:23, Kieran Bingham wrote:
> Hi Laurent,
> 
> On 14/02/2020 12:37, Laurent Pinchart wrote:
>> If one device fails to enumerate, which isn't supposed to happen under
>> normal conditions, both the sysfs and the udev enumerators stop
>> enumeration of further devices. This potentially prevents working
>> devices from being detected and handled. Fix it by skipping the faulty
>> device.
> 
> Thank you,
> 
> This does indeed allow the system to continue and function with the
> available cameras.
> 
> Interestingly, in the particular case that I was investigating - it
> wasn't the newly added device that failed ... it was the existing camera
> interface.
> 
> That can be investigated separately.
> 
> --
> Kieran
> 
> 
> 
>> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>


Thanks, indeed this now continues to function and produces an
appropriate message for the failing device components:


> [2:20:54.425174891] [3209]  ERR MediaDevice media_device.cpp:242 Failed to enumerate topology: Bad address
> [2:20:54.425281647] [3209] INFO DeviceEnumerator device_enumerator.cpp:217 Unable to populate media device /dev/media0 (Invalid argument), skipping
> [2:20:54.425393663] [3209] WARN DeviceEnumerator device_enumerator_udev.cpp:149 Failed to add device for '/sys/devices/platform/soc/fe801000.csi/media0', skipping
> Using camera VF0520 Live! Cam Sync: VF0520 L


Tested-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

And with one small comment considered below:

Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>






>> ---
>>  src/libcamera/device_enumerator_sysfs.cpp | 15 +++++++--------
>>  src/libcamera/device_enumerator_udev.cpp  |  8 +++++---
>>  2 files changed, 12 insertions(+), 11 deletions(-)
>>
>> diff --git a/src/libcamera/device_enumerator_sysfs.cpp b/src/libcamera/device_enumerator_sysfs.cpp
>> index ad26affb38a3..bde736226f95 100644
>> --- a/src/libcamera/device_enumerator_sysfs.cpp
>> +++ b/src/libcamera/device_enumerator_sysfs.cpp
>> @@ -33,7 +33,6 @@ int DeviceEnumeratorSysfs::enumerate()
>>  {
>>  	struct dirent *ent;
>>  	DIR *dir;
>> -	int ret = 0;
>>  
>>  	static const char * const sysfs_dirs[] = {
>>  		"/sys/subsystem/media/devices",
>> @@ -74,14 +73,14 @@ int DeviceEnumeratorSysfs::enumerate()
>>  		}
>>  
>>  		std::shared_ptr<MediaDevice> media = createDevice(devnode);
>> -		if (!media) {
>> -			ret = -ENODEV;
>> -			break;
>> -		}
>> +		if (!media)
>> +			continue;
>>  
>>  		if (populateMediaDevice(media) < 0) {
>> -			ret = -ENODEV;
>> -			break;
>> +			LOG(DeviceEnumerator, Warning)
>> +				<< "Failed to populate media device /dev/media"
>> +				<< idx << ", skipping";

Shouldn't this use something like media->deviceNode() ?

(Perhaps even printing media->driver() and media->model for guidance too?)


>> +			continue;
>>  		}
>>  
>>  		addDevice(media);
>> @@ -89,7 +88,7 @@ int DeviceEnumeratorSysfs::enumerate()
>>  
>>  	closedir(dir);
>>  
>> -	return ret;
>> +	return 0;
>>  }
>>  
>>  int DeviceEnumeratorSysfs::populateMediaDevice(const std::shared_ptr<MediaDevice> &media)
>> diff --git a/src/libcamera/device_enumerator_udev.cpp b/src/libcamera/device_enumerator_udev.cpp
>> index b2c5fd221dcd..3837aaf97e6a 100644
>> --- a/src/libcamera/device_enumerator_udev.cpp
>> +++ b/src/libcamera/device_enumerator_udev.cpp
>> @@ -145,10 +145,12 @@ int DeviceEnumeratorUdev::enumerate()
>>  			goto done;
>>  		}
>>  
>> -		ret = addUdevDevice(dev);
>> +		if (addUdevDevice(dev) < 0)
>> +			LOG(DeviceEnumerator, Warning)
>> +				<< "Failed to add device for '"
>> +				<< syspath << "', skipping";
>> +
>>  		udev_device_unref(dev);
>> -		if (ret < 0)
>> -			break;
>>  	}
>>  
>>  done:
>>
> 

-- 
Regards
--
Kieran