Created devices are not available
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
v4l2loopback (Ubuntu) |
Invalid
|
Undecided
|
Unassigned | ||
Focal |
Fix Released
|
High
|
Stefan Bader |
Bug Description
[SRU Justification]
Impact: The attempt to properly fix the warnings caused by the module in 0.12.3-1ubuntu0.1 caused any other application than Chromium to no longer detect available loopback devices. The tested capability was only set in the capabilities set, but not in the device_caps set.
Fix: The patch was modified to change the IOCTL code as it was done in v4l2loopback 0.12.5-1. This, probably contrary to what the kernel developers tried to achieve, works around the restrictions by additionally modifying the video device capabilities which the tests do check against.
Testcase: Now tested with OBS v4l2sink connected (and exclusive_caps set) against Chromium and Firefox. With 0.12.3-1ubuntu0.1 only Chromium would find the loopback camera but with the proposed update both Chromium and Firefox would work for me. And still no warnings.
Regression Potential: Essentially the difference to the released version is that with exclusive_caps set, then device_caps of the video device change. Which could throw off anything checking there and not expecting any change. On the positive side, this is now exactly the behavior that is exposed in 20.10/Groovy.
---
After the upgrade from 0.12.3-1 to 0.12.3-1ubuntu0.1 devices created using v4l2loopback are no longer available for use in applications (e.g. MS Teams and Zoom). With version 0.12.3-1 the devices would show up, e.g.
modprobe v4l2loopback video nr=2 card label="test"
would cause the new device to show up in those UIs as "test". With version 0.12.3-1ubuntu0.1 device "test" is no longer shown.
Downgrading to 0.12.3-1 fixes the problem.
Changed in v4l2loopback (Ubuntu Focal): | |
assignee: | nobody → Stefan Bader (smb) |
importance: | Undecided → High |
status: | New → In Progress |
Changed in v4l2loopback (Ubuntu): | |
status: | Confirmed → Invalid |
description: | updated |
tags: |
added: verification-done-focal removed: verification-needed verification-needed-focal |
tags: | added: verification-done |
tags: | added: regression-update |
This is using:
Linux euclid 5.4.0-52-generic #57-Ubuntu SMP Thu Oct 15 10:57:00 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux