I have just built fresh kernel, dtb, u-boot and sgx as per RCN eewiki and I have also built Qt 5.6.2.
Everything is working correctly except for one problem which I do not understand and hope somebody could explain.
After installing sgx drivers and a reboot I have everything as per instructions:
lsmod | grep omaplfb
omaplfb 12356 0
tilcdc 26717 1 omaplfb
pvrsrvkm 157212 1 omaplfb
but my Qt Quick programs only work when run as root (sudo).
Looking at the sgx-startup script, /dev/pvrsvrkm should be set with 666 permissions, but after startup this is what I get:
ls -al /dev/pvrsrvkm
crw------- 1 root root 247, 0 Nov 27 20:54 /dev/pvrsrvkm
When I run:
sudo /etc/init.d/sgx-startup.sh stop
sudo /etc/init.d/sgx-startup.sh start
I get:
sgx: Starting PVR
/usr/local/bin/pvrsrvctl: SrvInit failed (already initialized?) (err=129)
ls -al /dev/pvrsrvkm
crw-rw-rw- 1 root root 247, 0 Nov 27 21:48 /dev/pvrsrvkm
Permissions are now correct for running program as normal user.
my programs run correctly with platform eglfs - which is what I want.
My questions:
- Why does sgx-startup.sh not set the permissions correctly on boot and is there a way to solve this?
Thanks in advance
Rob
Oh let's patch that in the sgx-startup.sh script.. Probably after the
modprobe/pvrsrvct start..
Send me a patch and i'll push it out...
Regards,
Thank you Robert but I am not sure what you mean, would you kindly clarify.
As far as I understand the script, you are setting the permissions to 666 and you also start the service.
What I do not understand is how and why the permissions are not set when the script runs in the first place.
Rob
This is confusing me even more now - I added a “stat” on /dev/pvrsrvkm in the sgx-startup.sh, at the end before the “start” finishes and the permissions areset correctly -
debian@arm:~$ systemctl status sgx-startup
● sgx-startup.service - LSB: Start daemon at boot time
Loaded: loaded (/etc/init.d/sgx-startup.sh; generated; vendor preset: enabled
Active: active (exited) since Mon 2016-11-28 07:37:30 UTC; 1min 59s ago
Docs: man:systemd-sysv-generator(8)
CGroup: /system.slice/sgx-startup.service
Nov 28 07:37:27 arm systemd[1]: Starting LSB: Start daemon at boot time…
Nov 28 07:37:27 arm sgx-startup.sh[363]: sgx: Starting PVR
Nov 28 07:37:30 arm systemd[1]: Started LSB: Start daemon at boot time.
Nov 28 07:37:30 arm sgx-startup.sh[363]: 666 <<<<< just before the script completes
debian@arm:~$ ls -al /dev/pvrsrvkm
crw------- 1 root root 247, 0 Nov 28 07:37 /dev/pvrsrvkm
but still the permissions are 600 as can be seen above.
Any advice will be greatly appreciated.
Thanks
Rob
After hours of reading all sorts and my brain blowing up, I think I might have found the reason for the problem. However, as a Linux noob, I am now stuck and hope one of our gurus will shed light on this.
This is where I am now:
- Copied the “start” section of sgx-startup.sh to a new file and started fiddling.
- Found that there appears to be some delay between modprobe pvrsrvkm , deleting the /dev/pvrsrvkm file and what I assume is the kernel module setting permissions on the file.
- When I moved the delete and mknod to after the /usr/local/bin/pvrsrvctl --start --no-module and added a sleep 1, the file permissions were set correctly.
Unfortunately this only work when I run the script manually, it doe not work with reboot (maybe sleep cannot be used)
So, I am still trying to find a solution, but I am running out of things to try
Thanks
Rob
After spending some time with systemd and udec documentation and playing with udevadm I managed to find a solution.
No need to modify the sgx-startup.sh script, I just added a permission a sgx-permissions.rule to /etc/udev/rules.d with the folowing line - SUBSYSTEM==“pvr”, GROUP=“video”, MODE=“0660”.
I am not sure, maybe somebody can clarify - I think the chmod 666 /dev/pvrsrvkm has no effect since when modprobe is called, kernel and udev events will trigger and the default permissions for udev on devices is 600.
Regards
Rob