topic Re: AMT KVM or SOL Session Causes Target PC Screen to Flicker in Intel vPro® Platform

AMT KVM or SOL Session Causes Target PC Screen to Flicker

JPusk — Thu, 26 Sep 2013 16:21:24 GMT

Hi,

When I connect to any target PC on my vPro test network via SOL and\or KVM, it causes the target PC's screen to flicker about once every 10 seconds. The screen just goes black for a second or so, then comes back to whatever it was displaying. This flicker is OS independent and happens while I'm in the BIOS, during boot, while doing Dell diagnostics, and inside the OS itself. It happens on multiple models of Dell Optiplex (990 and 960). The target systems do not have any discrete graphics or network cards installed. They only have the Intel onboard graphics and nic.

For KVM, I'm using RealVNC 1.2.5 r111763.

For SOL, I'm using Manageability Commander v0.1.26.

I'm using Kerberos, but not TLS. I believe I have the simplest-possible SCS profile configured. Has anyone else experienced this 'flicker'?

Thanks!

Re: AMT KVM or SOL Session Causes Target PC Screen to Flicker

Alan_A_Intel — Thu, 26 Sep 2013 21:59:43 GMT

I haven't seen this before, but to be sure I tried this on a few of our Dell 960's and 990's. Neither had the issue of screen flickering on the vPro client. I would suggest updating to the newest BIOS and drivers, and try again.

Re: AMT KVM or SOL Session Causes Target PC Screen to Flicker

JPusk — Thu, 26 Sep 2013 22:11:27 GMT

Thanks Adam. I'm definitely on the latest BIOS and drivers as far as what's available on Dell or Intel's site (graphics, nic, SOL, IME; etc). I almost wonder if there's some weird L2/L3 issue like excessive packet fragmentation or TCP windowing errors or something.

Re: AMT KVM or SOL Session Causes Target PC Screen to Flicker

idata — Thu, 03 Oct 2013 18:55:06 GMT

This is actually an expected behavior for Intel's KVM when display is working in VGA mode (some BIOSes and DOS) . It is caused by integrated Gfx HW limitation of Intel's KVM for showing Sprite while the display is in VGA mode – in this mode it can't show the display image itself and the Sprite at the same time so when it shows the Sprite User Periodic Notification it can't show the screen itself.

For this reason the Sprite User Periodic Notification is done once in about 10 sec (instead of 3 sec for non-VGA mode).