USB to VGA adapter flicker... but not with movement

Scougar · 30 Sep 2015 at 15:00

I bought a cheap (keyword lol) usb to vga adapter the other day so I could get a third screen on my laptop.

Testing it at home, I plugged it into the USB 3.0 port and installed the drivers for it, and it works great, no issues. (This is at 1440*900, same as my third work screen)

I took it to work, and the alleged USB 3.0 ports on my HP Elitebook 8460p seem to make the screen flicker. I get a message come up saying: The xHCI Host Controller for this USB 3.0 port cannot display high resolution. So far I have tried the latest driver for the adapter, the latest USB 3.0 drivers (Renesas or whatever) and nothing seems to resolve the issue.

Now... here is where it gets weird. If I keep moving the mouse, or say, run a video on that screen the flickering completely stops.

Anyone got a clue?

wellibob · 30 Sep 2015 at 15:06

Some kind of refresh rate glitch I'd say. How to fix I dunno. Adjust the screens refresh rate perhaps ?

Scougar · 30 Sep 2015 at 19:55

Only allows me to have a refresh rate at 60hz on any of my monitors. Doesn't matter if I use DP, DVi, VGA or this adapter, 60hz only. (Intel HD 3000 graphics drivers if it matters). I have tried using fewer monitors as well, same thing.

I do not know why it reports the xHCI issue either, that should be fine as far as I can tell.

Scougar · 30 Sep 2015 at 21:41

Tried it on a 32 inch 1080p TV via VGA (same cable) and had the same problem. 1366 x 768 seemed to work fine on that tv though (I haven't tried that yet on the monitor).

I really think it is down the USB 3 ports/controller or something related to that.

EDIT: Was thinking about this a little, and something some mentioned on Youtube... I wonder if it's CPU limited. So when not moving the mouse for example, the cpu declocks and the flicker is there. It may be a cpu intensive component that isn't requested enough resource or something.

Scougar · 1 Oct 2015 at 13:31

Flicker does seem to reduce/stop around 25% cpu. Seems like the USB adapter (or whatever) isn't asking for enough resource. How do I bump the CPU to run at a minimum of 25% or whatever?

Armageus · 1 Oct 2015 at 13:36

Might be worth just bumping up the laptops speed settings (as it likely downclocks when it thinks it's idle)

Under Windows Power Options -> Edit Plan Settings :
Processor Power Management -> Minimum Processor State - Increase this

Scougar · 1 Oct 2015 at 13:37

Armageus said:
Might be worth just bumping up the laptops speed settings (as it likely downclocks when it thinks it's idle)

Under Windows Power Options -> Edit Plan Settings :
Processor Power Management -> Minimum Processor State - Increase this

Yeah... tried that already for minimum state... doesn't seem to do anything.