Which driver I need to use PeakCan in Qt6? - qt

Question

I need to use Peak System PCAN USB dongle in my Qt6 application.
At first I checked it works from command line.
In my Ubuntu 20.04 I have the kernel drivers installed:
$ grep PEAK_ /boot/config-`uname -r`
CONFIG_CAN_PEAK_PCIEFD=m
CONFIG_CAN_PEAK_PCI=m
CONFIG_CAN_PEAK_PCIEC=y
CONFIG_CAN_PEAK_PCMCIA=m
CONFIG_CAN_PEAK_USB=m
and loaded:
$ lsmod | grep ^peak
peak_usb 49152 0
I also tried to exchange data with can-tools and it worked out of the box.
Here the relevant output of the ip command:
$ ip addr
6: can0: <NOARP,ECHO> mtu 16 qdisc pfifo_fast state DOWN group default qlen 10
link/can
The problem arises when I try to connect from the Qt application:
std::unique_ptr<QCanBusDevice> _device;
QString errorString;
_device.reset(QCanBus::instance()->createDevice("peakcan", "can0", &errorString));
I get:
qt.canbus.plugins.peakcan: Cannot load library pcanbasic: (pcanbasic: cannot open shared object file: No such file or directory)
So I downloaded the PCAN Basic package.
In the readme there are the requirements:
System Requirements
-------------------
- PCAN Linux Driver: 8.0.17 and above
(Driver for Linux can be download at www.peak-system.com/linux)
So I compiled and installed the drivers. Now the peakcan plugin is found:
qt.canbus.plugins.peakcan: Using PCAN-API version: 4.5.2.15
but now:
no device is discovered by Qt
ip addr shows no can devices
lsmod | grep ^peak shows no drivers loaded
Question #1: am I missing anything in order to get it works?
By the way, in the Linux driver page they also state:
The CAN interfaces are then accessed via the common SocketCAN framework as network devices
Hence I tried to find any available device using socketcan:
QString errorString;
const QList<QCanBusDeviceInfo> devices = QCanBus::instance()->availableDevices(QStringLiteral("socketcan"), &errorString);
if (!errorString.isEmpty()) qDebug() << errorString;
foreach (QCanBusDeviceInfo info, devices)
{
qDebug() << info.name();
}
but it finds no devices.
If I try to connect to it:
std::unique_ptr<QCanBusDevice> _device;
QString errorString;
_device.reset(QCanBus::instance()->createDevice("socketcan", "can0", &errorString));
I get:
RTNETLINK answers: Operation not permitted
I guess because I'm running the application with user privileges.
I get the same error if I try to bring the interface up without sudo:
$ ip link set can0 up
RTNETLINK answers: Operation not permitted
Question #2: Is there any group I need to join to in order to let Qt6 to bring up the network device without root privileges?