I am trying to retrieve and parse EDID metadata from a snap - without success.
If I install my snap in --devmode, I can actually do this, but I can’t figure out which interface I need to connect to in order to retrieve EDID data in confined mode.
Does anyone have a clue?
Run the snappy-debug command (from the same named snap) in a second terminal while you run your snap… it should make suggestions about interfaces
Thank you @ogra! After your suggestion I was able to get a better picture of what is going on.
This is what apparmor is denying
Log: apparmor="DENIED" operation="file_mmap" profile="snap.read-edid-test.get-edid" name="/dev/zero" pid=175222 comm="get-edid" requested_mask="m" denied_mask="m" fsuid=0 ouid=0
File: /dev/zero (mmap)
Suggestion:
* verify program isn't using an executable stack: https://forum.snapcraft.io/t/snap-and-executable-stacks/1812
With a little searching on the forum, I found this AppArmor denial for /dev/nvidiactl - #4 by jdstrand which is a pretty similar problem. Then I looked at what is suggested here Snap and executable stacks, but I am not quite sure how to approach the problem.