Configuration issue in kernel 4.14.146-bone29

[TJF]

I'm using the uio_pruss driver. And I'm trying to configure the /dev/uio[0-7] files early in the boot sequence. I need to setup a certain group for some of them.

But my setting gets overwriten later in the boot sequence. I found the file /etc/udev/rules.d/uio.rules causing one override. But even deleting that file doesn't help, my initial setting gets overriden. And I cannot find the process causing that problem.

Does anybody know which process[es] override the group setting of /dev/uio[0-7]?

Thanks in advance.

[Robert Nelson]

Just the kernel defaults and our custom /etc/udev/rules.d/uio.rules

Regards,

--
Robert Nelson
https://rcn-ee.com/

[TJF]

Hi Robert, thanks for the answer!

In my systemd service I wait for the files, then change the ownerchip like

ExecStartPost=/bin/dash -c 'until [ -e /dev/uio5 ] ; do sleep 1 ; done ; /bin/chown root:pruio /dev/uio5'

This works, I checked it by the ls command output

ExecStartPost=/bin/dash -c 'ls -l /dev/uio5 > /tmp/x ; sleep 1'
ExecStartPost=/bin/dash -c 'for i in 1 2 3 4 5 6 7 8 9 ; do ls -l /dev/uio5 >> /tmp/x ; sleep 1 ; done'

The group is correct for six seconds and then changes back to root:root !

Does the kernel driver set the ownership twice now? Or is there any action from the device tree?

Any help is much appreciated.

Regards