DisplayLinkManger crashing 1.1.62

[DIT]

My company is attempting to integrate the DL3 drivers into our distribution of Linux. We have everything packaged, and it seems to be attempting to correctly use the DL3 docker that we have, however DisplayLinkManager is repeatedly crashing (exit code 0, lots of minidump files).

We have tested this with Ubuntu 16.04 and Arch Linux so we know it should be working. We have tried to find and follow all official requirements and documentation.

I am attaching the contents of /var/log/displaylink in a zip file.

- We are using Linux 4.4.6 on Intel skylake CPU.
- Module(s) load fine (udl, evdi [from github])
- systemd service starts
- We never see it as a provider in xrandr (xrandr --listproviders) before the service dies with an exit code of 0 and restarts.

We expect that there is some undocumented need that we have not discovered yet in order to be able to meet.

[DIT]

Here is the content from the DLSupportTool as well.

[mlukaszek]

Doesn't look like DisplayLinkManager is running with enough privileges to write to sysfs entries, that's why it's crashing. Note that on Ubuntu we use systemd/upstart to make it run as root.

Regards,
Michal

[DIT]

Indeed we have it running as root with systemd as well, per the systemd files present in the installer.

I may need to re-run some reports via root vs the user account (oops?), but everything lines up to the way the installer would have had them.

[mlukaszek]

What's failing on this system is a call to int evdi_add_device() (https://github.com/DisplayLink/evdi/blob/devel/library/evdi_lib.c#L270) from libevdi.

What doesls -la /sys/devices/evdi return?

Cheers,
Michal

[DIT]

# find /sys/devices/evdi/
/sys/devices/evdi/
/sys/devices/evdi/add
/sys/devices/evdi/count
/sys/devices/evdi/power
/sys/devices/evdi/power/control
/sys/devices/evdi/power/runtime_active_time
/sys/devices/evdi/power/autosuspend_delay_ms
/sys/devices/evdi/power/runtime_status
/sys/devices/evdi/power/runtime_suspended_time
/sys/devices/evdi/remove_all
/sys/devices/evdi/module
/sys/devices/evdi/version
/sys/devices/evdi/uevent
/sys/devices/evdi/loglevel

# ls -la /sys/devices/evdi/
total 0
drwxr-xr-x 3 root root 0 Jun 16 11:35 .
drwxr-xr-x 19 root root 0 Jun 16 11:35 ..
--w------- 1 root root 4096 Jun 16 11:33 add
-r--r--r-- 1 root root 4096 Jun 16 11:35 count
-rw-r--r-- 1 root root 4096 Jun 16 11:35 loglevel
lrwxrwxrwx 1 root root 0 Jun 16 11:35 module -> ../../module/evdi
drwxr-xr-x 2 root root 0 Jun 16 11:35 power
--w------- 1 root root 4096 Jun 16 11:35 remove_all
-rw-r--r-- 1 root root 4096 Jun 16 11:35 uevent
-r--r--r-- 1 root root 4096 Jun 16 11:35 version

[DIT]

Hopefully the attached log (properly run as root) will provide further insight. This one is from a Braswell family, but the same kernel setup. Our guess is still some missing bits of dependencies we're missing.

[mlukaszek]

Do you see the same problem if you take libevdi.so from HEAD of devel branch at https://github.com/DisplayLink/evdi (you obviously need to build the binary yourself)?

Thanks,
Michal

[DIT]

I can certainly give it a whirl. We are currently using the module and library from https://github.com/DisplayLink/evdi/tree/v1.1.65

[DIT]

I have attached the logs when using evdi.ko & libevdi from branch devel

[mlukaszek]

Do you have the modesetting module for X installed? Doesn't appear so.

Cheers,
Michal

[DIT]

That does appear to be missing from that system image.

Did we miss that in the requirements documentation somewhere? :o

/edit
That fixed it, and it is functional now.

Should /usr/lib/displaylink/DisplayLinkManager be eating a large amount of CPU (most of or more than 1 core) ?

[mlukaszek]

Glad it's fixed. The CPU usage - it depends. It is discussed in more detail here (http://displaylink.org/forum/showpost.php?p=80403&postcount=21).

Cheers,
Michal