DisplayLink software resets with quad monitors

[Carlo]

I think it's a power problem. From the logs is seems that one adapter is sometimes falling off the bus, probably because it does not receive enough power, and then come back.
It looks like you have 4 adapters connected to a single hub. They are all nearly at maximum resolution so they're going to draw maximum current when something is moving on the screen. A standard 4 port hub power supply can't usually power more than 2/3 adapters in these conditions. A 7 port hub supply can usually power 3/4.
I'd move at least one adapter to a different hub or connect it directly to the computer, or buy a bigger power supply for the hub.

Carlo

[oldtopos]

Carlo,

Sounds plausible, as they are all connected to a single 10 port hub.

Early testing indicates better behavior with four monitors.

[oldtopos]

Carlo,

Moving one adapter off the USB hub did stabilize the system.

However, the hub is rated at 2.5 Amps, and this should be sufficient for four USB devices running at 500ma max. It's a 10 port Pluggable http://plugable.com/products/usb2-hub10s/

Are the adapters capable of drawing more than 500ma each ?

[Carlo]

Originally Posted by oldtopos

Carlo,

Moving one adapter off the USB hub did stabilize the system.

However, the hub is rated at 2.5 Amps, and this should be sufficient for four USB devices running at 500ma max. It's a 10 port Pluggable http://plugable.com/products/usb2-hub10s/

Are the adapters capable of drawing more than 500ma each ?

We've seen adapters draw more than 500mA for high resolution digital connections yes. We've also seen some that are always below 500mA, but they tend to be much more expensive because the power circuitry is not cheap. Don't ask me the brand.
It usually depends on the electronics so it's a question for the device manufacturer really.

I any case when budgeting power for video adapters I'd consider them like external 2.5" HDs: up to 40% more than 500mA in peak conditions.
If you consider the power regulator efficiency inside the hub and other low power devices that might be connected you don't' have more than 3 adapters for a 2.5A power supply.

Carlo