Purple PS/2

Does Qubes treat purple PS/2 the same way as green/blue?
I need to know for sure before buying mother board.

purple - keyboard
green - mouse
blue - don’t know what’s that


You’re absolutely right. It’s half green, half purple.
This is the motherboard I’m looking at:

This mean it supports a keyboard or a mouse on that port

Yes, this is a combo port apparently.

Does Qubes support it for 100%?

It should work if it works in Linux in general (or Fedora specifically) but nobody will give you 100% guarantee without actually testing it out.

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Well in Linux in general it obviously should work, as every other port(are there any that don’t?).

Just wanted to make sure this combo port will be treated by Qubes as regular PS/2.
If there’s anyone with that kind of port in here, please let know

I guess it should work, Qubes OS doesn’t do any special treatment on these ports

Just remember that usually, PS/2 ports are not hot-plug, you need to plug the device on it before turning the computer ON, otherwise it won’t do anything.


There sure are. There could be some PCI device that only has proprietary drivers for Windows and doesn’t support Linux at all and nobody cared about it enough for reverse engineering.


I’ve seen mainboards with a SCART port :scream:

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What should I ask from the provider exactly so I would know Qubes will treat it the same as the mouse/keyboard PS/2, if this PS/2 is… what? Not hot-plug?

PS/2 ports are never hotplug IIRC, but it only mean you need to power down the device before connecting something on it, and then power it up. Whereas USB ports can be plugged in and removed on the fly.

Yeah, I got that part, It just in documentation there’s no underline explanation of what and why, and at forum the closest thing is something like that: Why are a PS/2 keyboard and mouse recommended out of curiosity?
But that just doesn’t even tell me what I should ask in order to ensure the compatibility with Qubes. Or should I just go with it and pay&pray?

There’s no reason PS/2 devices not to work with Qubes. What the question is, is behind PS/2 port a PS/2 controller, or USB controller. That’s what you should check in advance, at least I’d do.

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I am not sure what value you get from a mainboard with a single PS/2 port for keyboard or mouse. Don’t you need both in order to run a proper system?

And they make PCIe cards with both PS/2 ports and a couple USB. That seems to me like the right thing to do if you don’t have native ports on a mainboard.

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  1. IIRC (It’s been a while) some motherboards had a single ps/2 port for mouse/keyboard and require therefore required a ps/2 y-cable to support both keyboard and mouse

  2. Any PCIe card with PS/2 ports on it is just a USB controller that also translates ps/2 signals to USB signals effectively making ps/2 keyboards/mice into USB ones.

It’s not actually possible to to support “real” ps/2 connectivity via PCIe because the ps/2 devices are accessed via a part of the system that existed pre-PCIe (pre PCI even).

The PCIe card with PS/2 ports just gets you another USB controller you have to either manage via sys-usb or directly attach to dom0.



I bought USB to PS/2 dongles for keyboard and mouse, they didn’t work. Had to get a proper keyboard/mouse with PS/2 before Qubes would behave.

There are two kinds of PS/2 to USB adapters (dongles), active and passive.

Active adapters internally convert USB signaling to PS/2 signaling and vice versa, should work in all USB ports.

Passive dongles work only on (old, now rare) on-board USB 2.0 and lower (or maybe only USB 1.1 and lower?) USB ports that also have motherboard support for internally converting PS/2 signaling to something the motherboard understands. I think it’s also converting them to USB devices in all/most cases, but I could be wrong on that point. However, this conversion happens on the motherboard instead of in the adapter.

So, if you have a passive adapter it won’t work in most USB ports you encounter these days. It’s hard to tell from looking at the adapter what kind it is.


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Wow, wish I’d asked here before wasting $7 or whatever on Amazon :slight_smile: