Re: Wonky PS2-USB converter issues...

From: Alan Stern
Date: Thu Feb 21 2013 - 10:50:58 EST

On Wed, 20 Feb 2013 Valdis.Kletnieks@xxxxxx wrote:

> On Wed, 20 Feb 2013 16:07:49 -0800, Greg Kroah-Hartman said:
> > PS-2 connectors can not normally handle hotplugging, the protocol
> > doesn't allow it, and for some unlucky devices, it could actually fry
> > the motherboard or the PS-2 device.
> >
> > So that's probably the issue here, the device just doesn't support it,
> > sorry.
> You mis-understood the problem.
> This works:
> PS/2 keyboard plugged into this device:
> Bus 006 Device 002: ID 0e8f:0020 GreenAsia Inc. USB to PS/2 Adapter
> USB side of device plugged into USB port on the Latitude laptop.
> Power up, boot - the keyboard works.
> If you plug the USB side of the GreenAsia adapter into a USB slot on
> the dock, the keyboard is dead and not recognized by the system. However,
> replugging the USB, or unplug/plug the PS/2 side, and it becomes recognized
> and starts working.
> This tells me that the dock is doing something busted with USB that the laptop
> does correctly, and not enumerating devices until something happens to whack it
> upside the head. I was hoping to identify it and maybe quirk it.

What happens if you prevent ehci-hcd from being loaded during boot and
then load it manually afterward? Does the keyboard/adapter/dock
combination work then?

If it doesn't, try recording a usbmon trace.

Alan Stern

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