Screen briefly black out and comes back running Horizon client on IGEL OS 11.05.100 and 11.05.112


Hello, we’ve been testing the new 11.05.100 release and 11.05.112 and we seem to have the exact problem on both releases, video issues related to sound events. The weird issue experienced is that on the Horizon client everytime there’s a notification that includes sounds, the screen briefly blacks out and comes back. It also happens when you connect or disconnect a headset. I was able to correct the issue by reverting back to 11.04.270. Anybody else experiencing this? Hardware being used is Dell/Wyse 5070. Thanks

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Hello, Roberto, interesting! Are you using Native USB Redirection and / or RTAV?

kb.igel.com/igelos-11.05/en/usb-redirection-42010885.html

kb.igel.com/igelos-11.05/en/multimedia-42010890.html

Could you share your settings there?


I’d like to add I’m seeing this same issue on 11.05.110 WYSE 5070 in Citrix. Sound events make the screen black out for about half a second

Sorry for opening a new thread, I just saw OP was Horizon and we’re Citrix so figured it was different. You sent Horizon articles, is there a place you’d like me to report my settings for Citrix ?


No reason to be sorry Bryan🙂 I don‘t wanted to „sound“ rude😓

Yes, exactly: Native Usb redirection and if local played sounds do the same. Here is a gif how to test last one:


Native USB redirection is enabled. Default rule allow, though I guess I could change that to deny. Do you think I should see if we get the same experience if I change it to deny? We’re still trialing iGel as a possible replacement solution here so I do appreciate the support even though we’re not paying just yet!


Well, Native USB redirection set to ON and AllowAll is a bit dangerous IMHO. You might have devices who went redirected that aren‘t designed for that: Headsets is one example. So, yes, please set it to Deny, reboot and retry. If you have time, please check also if the local sound test provides the same behavior (if yes, highly improbable that the USB Redirection is the issue 😀


Hello everyone, IGEL support and development have started tracking this issue. I would like to request that cases be submitted for this. This is happening on the local OS with local sounds, so any sound generated does this.

At this time, it only appears to happen on a very specific revision of the 5070, and only with specific monitor configurations or possibly display cables.

We have a device in hand and still cannot reproduce the issue in-house.

If you open a case, can you please provide the data below?

• IGEL OS Version

• Monitor Make / Model

◦ Resolution / configuration

• Connected Monitor Count (We only see this with two displays or more so far)

• Cable make / model

• Device configuration exports

• lshw (results if possible)


Hi @member.. We’re trialing iGel so I can’t open a support case. I’m still happy to help, especially considering if we do use iGel we’ll have a number of WYSE 5070s with a similar config. It happened to us on 11.05.110. We use two monitors, Dell P2317H. We just use various third party cables, these are connected via DP. Happy to work with an engineer who wants to gather any info to help them capture this bug

N11D .. N11D001 are the WYSE5070 HW revisions it appears via the info tag on the pull out

Attached is an image of what ports we’re using

Attached I have standard headphones in the front analog port for audio, a logitech wireless mouse USB receiver, a Microsoft USB Webcam Lifecam HD-3000


Hello, i did have the USB redirection/RTAV ON. i can disable USB redirection like you said to minize USB devices reported to the host side. But on the RTAV it’s another issue, i’m using Webex Meetings on the host side and RTAV is the only way i can get it to use sound/video with no so good optimized (offload) quality…in the mean time i will re-upgrade my thin to OS11.05.112 and let you know the outcome…Monitors P2419H DP, Logitech C925e, Jabra 30 USB headset or H151 standard headset


@member are you able to test on the local IGEL OS before starting a VMWare session?

Also, USB audio devices don’t seem to trigger this in other instances. Only built-in speaker or analogue.


Yes i did, and it did the same, regardless if it’s usb or not. Disabling USB, seems to have done the trick…but let me check again…i will activate it back, since i’m on 11.05.112

…As soon as i enable it (USB) redirection i get the issue.


Ok, that‘s interesting! Thank you for that feedback! @member


Hi @member. Thank you very much for the additional information! Just to clarify, the last test that you did with disabling the USB redirection, was this resolving the issue on the local IGEL OS? Or were you still testing with the Horizon session?


I turned off USB redirection in Citrix and I’m still having the issue. It occurs even when I’m not in a Citrix session


Thank you @member! That is what I expected, but wanted to confirm.


I was testing only on the Horizon side. But to confirm with you, on the IGEL side on firefox i get the issue when the RTAV is set to off and usb is still off…So i guess the issue is with 10.0.5.100-112 still

i’ll revert back to 11.0.4.270


Alright, we found out a solution to this. You have to disable power saving for the intel HDA sound card.

It appears intel modified their driver, and what we assume is happening is that in older versions the card would go into a “low-power” state. In the new version it powers the audio card off completely when not used, and when it powers back on it emits a small amount of EMF, which is knocking the display out of sync. Most monitors can deal with a small blip, but some monitors (Cheaper Dell monitors in our testing) cannot deal with it and go “offline” briefly.

The fix is to modify the kernel parameter and disable the power save timeout to “0”.

The profile below uses an IGEL registry key to do just this. Let me know if this doesn’t fix it for you 🙂

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