V4L2Loopback issues when enabling webcam on RHEL 8.6

[obsidian84]

Hello all,

We're in the process of configuring RHEL 8.6 desktops and are running into an issue when trying to enable the RTAV feature in the Horizon Agent (2203). I'm using this string to configure the agent (after reviewing Command-line Options for Installing Horizon Agent for Linux (vmware.com)) :viewsetup.sh -a yes -f yes -m yes -A yes -C yes -F no -P yes -S yet -T no --webcam. It fails with the --webcam flag with this error: Error: Miss v4l2loopback-ctrl, please refer to guide to build and install v4l2loopback driver and v4l2loopback-ctl. Running without --webcam results in a successful configuration.

I followed this guide to install the V4L2Loopback Driver using the RHEL instructions: Install the V4L2Loopback Driver (vmware.com)

I've tried both with the v0.12.5 and v0.12.7 releases of the v4l2loopback driver. The installation of V4L2Loopback does not produce any particular errors and seems to be successful. Running modprobe V4L2Loopback does not produce additional messages, but running modprobe V4L2Loopback-ctl returns this error: modprobe: FATAL: Module v4l2loopback-ctl not found in directory /lib/modules/4.1.8.0-372.16.1.el8_6.x86_64.

I found the v4l2loopback-ctl file inside /usr/local/bin. Copying it into the directory above still results in the same errors when running both modprobe and viewsetup.sh.

I'd appreciate any guidance so I can get RTAV working. Thank you!

[Hangl]

v4l2loopback-ctl is a command line tool, but not a module.

 Error: Miss v4l2loopback-ctrl, it means installer cannot find it in PATH. Please check if the following command works,

which v4l2loopback-ctrl

If it works, please try installing again by using install_viewagent.sh instead of viewSetup.sh.

[obsidian84]

Thank you for the reply!

which v4l2loopback-ctl produces a result of /usr/local/bin/v4l2loopback-ctl

I should have specified in my original post, but we used the RPM installer, which does not seem to include the install_viewagent.sh file like the Tarball installer. From this, it looks like viewagent.sh would be the correct option to use? Command-line Options for Installing Horizon Agent for Linux (vmware.com).

I also followed the recommended installation sequence for the RPM installer, where the view agent was installed before installing the V4L2Loopback driver: Install the Real-Time Audio-Video Feature (vmware.com)

I will try the Tarball Horizon Agent installer and see if we get anything different from the RPM Installer.

[songkai]

Hi obsidian84

      What the result of "modprobe v4l2loopback"  and "modinfo v4l2loopback"? Please node:

1) Please only use the 0.12.5 v4l2loopback, and please apply the patch [agent install folder]/resources/v4l2loopback/v4l2loopback.patch to the 0.12.5 v4l2loopback before build it. 

2) RHEL 8 request signed the driver, please refer to https://docs.vmware.com/en/VMware-Horizon/2206/linux-desktops-setup/GUID-F3F2D262-62DA-4DFC-810D-FFE... for the v4l2loopback driver build  and install.

[obsidian84]

---

@songkai wrote:

Hi obsidian84

      What the result of "modprobe v4l2loopback"  and "modinfo v4l2loopback"? Please node:

1) Please only use the 0.12.5 v4l2loopback, and please apply the patch [agent install folder]/resources/v4l2loopback/v4l2loopback.patch to the 0.12.5 v4l2loopback before build it. 

2) RHEL 8 request signed the driver, please refer to https://docs.vmware.com/en/VMware-Horizon/2206/linux-desktops-setup/GUID-F3F2D262-62DA-4DFC-810D-FFE... for the v4l2loopback driver build  and install.

---

Hi songkai,

Thank you for your reply.

modprobe v4l2loopback does not return any messages when ran.

modinfo v4l2loopback returns:

filename:       /lib/modules/4.18.0-372.16.1.el8_6.x86_64/extra/v4l2loopback.ko
alias:          char-major-10-255
license:        GPL
version:        0.12.5-vmw
author:         Vasily Levin,IOhannes m zmoelnig <zmoelnig@iem.at>,Stefan Diewald,Anton Novikovet al.
description:    V4L2 loopback video device
rhelversion:    8.6
srcversion:     DF9AC1B9FFD6D295236144C
depends:        videodev
name:           v4l2loopback
vermagic:       4.18.0-372.16.1.el8_6.x86_64 SMP mod_unload modversions
sig_id:         PKCS#7
signer:         Descriptive name
sig_key:        15:FD:A0:10:12:BC:E0:FE:B1:4C:E6:4F:39:FC:A6:54:00:63:DA:59
sig_hashalgo:   sha256
signature:      4A:7C:C8:7F:BA:63:4E:12:F8:97:C5:7C:CC:8C:87:E1:22:D7:CB:AD:
		27:D5:3B:DA:F5:86:61:9F:FE:F4:46:5A:D1:00:83:90:84:87:22:C7:
		5A:2C:B6:0D:46:CB:A4:A7:C3:2D:26:BE:A2:3F:43:F6:54:F4:4D:18:
		58:11:FD:75:36:6D:07:51:40:B1:D6:8A:21:96:3B:BA:BF:68:EB:0F:
		70:18:D2:68:F5:61:0A:3F:AA:36:B0:0B:51:F4:45:4A:95:20:60:1B:
		68:22:85:AF:E4:19:C8:62:BE:43:C5:56:A3:C7:80:40:16:5C:3B:E0:
		11:C7:CA:E4:71:C1:62:62:5F:66:8C:51:B8:40:11:86:78:D7:20:B2:
		57:76:19:3A:AF:8F:D9:70:B0:CE:7E:C8:DB:7D:82:A5:FC:D7:71:95:
		15:AC:EF:E2:F5:F9:80:D6:A8:B1:33:57:D9:AC:C2:C9:08:A0:EB:0F:
		1F:07:D3:56:5D:CB:1E:C1:17:CD:F1:EE:50:0D:0E:1A:18:91:07:8F:
		40:7D:16:CF:75:0E:62:1E:68:A6:50:55:8C:9E:70:7B:55:B1:37:6D:
		CA:54:B6:72:39:F0:7C:18:87:C8:08:B3:C7:F1:36:1B:27:E1:3C:7B:
		C8:F4:76:68:93:F2:47:6D:40:76:7B:DA:4C:34:93:82
parm:           debug:debugging level (higher values == more verbose) (int)
parm:           max_buffers:how many buffers should be allocated (int)
parm:           max_openers:how many users can open loopback device (int)
parm:           devices:how many devices should be created (int)
parm:           video_nr:video device numbers (-1=auto, 0=/dev/video0, etc.) (array of int)
parm:           card_label:card labels for every device (array of charp)
parm:           exclusive_caps:whether to announce OUTPUT/CAPTURE capabilities exclusively or not (array of bool)
parm:           max_width:maximum frame width (int)
parm:           max_height:maximum frame height (int)

1) Including this reply, the test machine only has version 0.12.5 installed. I installed 0.12.7 on a separate machine to see if I would get a different result. The patch was also applied before building v4l2loopback as instructed in the guide.

2) I've followed those instructions to build and install v4l2loopback and the signed the driver.