Re: [gentoo-user] [OT]: "Reset" of USB when switching to console and back to X?

[meino.cramer@gmx.de]

Paul Hartman <paul.hartman+gentoo@gmail.com> [11-08-17 21:08]:
> On Wed, Aug 17, 2011 at 1:42 PM,  <meino.cramer@gmx.de> wrote:
> > Paul Hartman <paul.hartman+gentoo@gmail.com> [11-08-17 18:02]:
> >> On Tue, Aug 16, 2011 at 10:01 PM,  <meino.cramer@gmx.de> wrote:
> >> > Hi,
> >> >
> >> > I have attached an old keyboard (PS/2-connector) via an
> >> > USB-PS/2-adaptor to my PC.
> >> >
> >> > When typing too fast (...) the three LEDs of the keyboard flashes
> >> > and everything typed then is typed as if the CTRL-Key constantly
> >> > locked (I am using the X-window-system with openbox as windowmanager.
> >> > There is no session management.)
> >> >
> >> > It is possible to revert back to normal when I switch
> >> > from X-windows to the Linux console (CTRL-ALT-F1) and back
> >> > to X (CTRL-ALT-F7).
> >> >
> >> > My question is:
> >> > What part (PC? Adapator? Keyboard?) gets out of sync here is
> >> > "resetted" (somehow), while switching between console and
> >> > X-windows?
> >> >
> >> > How can I reset the behaviour without switching? How can I
> >> > prevent the behaviour completly?
> >>
> >> FWIW I have experienced that same behavior with several PS/2 to USB
> >> adapters, in Windows, in Linux, etc. I think it's a common problem
> >> with those adapters in general. I've never used one that didn't "go
> >> crazy" a few times a day.
> >>
> > Hi Paul,
> >
> > after some recursive investigations :) via internet I found some
> > interesting things:
> > 1) Yes, your are completly right: It is the USB-PS2-adapter, which
> > goes crazy.
> > 2) No, you are wrong, the reason is different.
> > ;) :)
> > 3) The answer is 41.999998 (calculated by a P90). ;)
> >
> > The reason for stuck CTRL/SHIFT keys is a missing pull-up
> > resistor from the clock and the data line to the +5V line
> > of the PS2 connection. Or in other words: Adding these resistors
> > seem to fix the problem in most cases.
> > See the link below (which describes the process for a IBM Model M keyboard. Seems true
> > for other old PS2 keyboards as mine, too):
> > http://ps-2.kev009.com:8081/ohlandl/keyboard/modify_keyboard/Model_M_Modifications.html
> >
> > The PS2 goes crazy because the high level gets too low without the
> > additonal pull up resistors. But the "origin of the reason" is not
> > the adapter, but the low high levels of the old PS2 line as such.
> >
> > I did find these information that late (after posting to this list)
> > by searching for informations about certain different usb-PS/2-adapter.
> > Sorry, when answering the other half of my own question.... :)
> 
> Very interesting info, it's good to know the real reason why it always
> seems like a "universal" problem with those adapters.
> 
> In the end, to solve my own problem, I bought two Unicomp keyboards
> which are the same as the old heavy IBM keyboards but with USB
> built-in. ;)
> 

(my question is based only on curiosity...)

Are the Unicomp Model Ms of the same quality and tactile/audible
feeling as the original IBM model Ms?

Best regards,
mcc