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Devices not getting displayed under /dev

Posted: Fri 11. Sep 2020, 08:01
by vijayendranss
I use PCAN Driver for Linux v8.
Few general queries :
After succesfull compilation when i do execute

Code: Select all

sudo modprobe pcan
lspcan -T -t -a 
Devices are not getting displayed under /dev
Note : I have not connected actual device or hardware in my PC.

Is it exepcted behavior ?
or
regardless of actual device connection of the devices, those should get displayed ?

Which is expected behavior ?

Re: Devices not getting displayed under /dev

Posted: Fri 11. Sep 2020, 08:03
by M.Heidemann
Hello,

This beheaviour is expected. The devices only show up if connected.

Best Regards

Marvin

Re: Devices not getting displayed under /dev

Posted: Fri 11. Sep 2020, 08:24
by vijayendranss
Hi Marvin,
Thanks for the reply.. But one query.
I used some other LKM. This will create virtual devices under /dev.
I used insmod for this and i can see al lthe devices under /dev.

Infact, modprobe also in turn uses insmod. Why there is different behavior ?

I want somehow the devices to be displayed without connecting. Any suggestions ?

Re: Devices not getting displayed under /dev

Posted: Fri 11. Sep 2020, 14:02
by M.Heidemann
Hello,

Other LKM, can you please clearify which?

Suggestion here would be to take a look at the documentation and have a look at the chapter Udev rules (4.2),as it will show you, what the Udev rules a doing by default.

You can choose not to use Udev and create the devices manually.

Quote from the docuemntation (page 18):

"With a properly configured and running Udev system, all of these devices files and directories are generated on the fly. If the target non-RT system does not have a running Udev system, you must create the device files manually each time after driver installation. The driver package provides the shell script driver/pcan_make_devices for this. For example, to create a maximum of 2 devices of each type"


Best Regards

Marvin