I have a KVM USB 2.0 switch connected to my Thinkpad laptop and my
Athlon desktop computer. The KVM Switch is from Cables Unlimited (I
just bought it at TigerDirect). I have a removable drive drawer
installed on my desktop computer. When I have Windows running on both
computers, the KVM switch works ok (i.e., hitting the Scroll Lock key
twice switches which computer my monitor is connected to). However,
when I boot up Red Hat Linux 9 on my desktop the KVM switch no longer
works. I think the X-Window system is disabling the Scroll Lock key.
Is there any way to get my KVM switch to work with Linux? Thanks!

Mark

On 2005-10-29, Mark <mkhuebner@gmail.com> wrote:
> I have a KVM USB 2.0 switch connected to my Thinkpad laptop
<zap>
> works. I think the X-Window system is disabling the Scroll Lock key.

I've a similar KVM and had no problem with or without Linux.
But if you think that is XWindow, just don't start it and try
from the console. Check the documentation of that thing, can't you
change the 'hot key'?

Davide

--
To me it sounds like a flock of ducks trying to out-honk a Mac Truck, but
getting cut short tragically as they all fly into the grill work of the truck.
But that's just me.
-- Paul Tomblin, about the system beep on the Alpha UDB

On 29 Oct 2005 12:48:51 -0700 "Mark" <mkhuebner@gmail.com> wrote:

> I have a KVM USB 2.0 switch connected to my Thinkpad laptop and my
> Athlon desktop computer. The KVM Switch is from Cables Unlimited

Yea, I've heard they, uh, suck, for lack of a better term.

--
remove MYSHOES to email

On 29 Oct 2005 12:48:51 -0700, Mark
<mkhuebner@gmail.com> wrote:
> when I boot up Red Hat Linux 9 on my desktop the KVM switch no longer
> works. I think the X-Window system is disabling the Scroll Lock key.
> Is there any way to get my KVM switch to work with Linux? Thanks!
>
Try a more recent Linux distro like FC4, Sarge or Ubuntu.


--
A man of genius makes no mistakes.
His errors are volitional and are the portals of discovery.
-- James Joyce, "Ulysses"

On Sat, 29 Oct 2005 21:48:51 +0200, Mark <mkhuebner@gmail.com> wrote:

> I have a KVM USB 2.0 switch connected to my Thinkpad laptop and my
> Athlon desktop computer. The KVM Switch is from Cables Unlimited (I
> just bought it at TigerDirect). I have a removable drive drawer
> installed on my desktop computer. When I have Windows running on both
> computers, the KVM switch works ok (i.e., hitting the Scroll Lock key
> twice switches which computer my monitor is connected to). However,
> when I boot up Red Hat Linux 9 on my desktop the KVM switch no longer
> works. I think the X-Window system is disabling the Scroll Lock key.
> Is there any way to get my KVM switch to work with Linux? Thanks!

I can't imagine your X server disabling the scroll lock key, I
would think that the KVM sees the key events before the computer.
The computer only sees them if the kvm forwards them. Disabling the
key would only mean the key did not affect anything in the computer.

I have seen there are a couple of USB devices that work well with
Windows but not with Linux. I have also seen that the latest
FC4 kernel update changes a couple of things to make it emulate
Windows more closely when querying the devices about their
configuration data. This reportedly helped for some device that
did not work, but at the expense of others that used to work,
but no longer do.

Does your Linux box see the keyboard etc? Check the /proc/bus/usb/devices
file. Lines starting "T:" start a new device entry. Expect to see the kvm
as hub device with the keyboard, mouse and monitor as connected devices.
The kvm should pretend to each computer (i think) the devices are there
all the time.

-Enrique

"Enrique Perez-Terron" <enrio@online.no> wrote in message
newsp.szfm1enwnxtvbs@apeiron.home.lan...

> I can't imagine your X server disabling the scroll lock key, I
> would think that the KVM sees the key events before the computer.
> The computer only sees them if the kvm forwards them. Disabling the
> key would only mean the key did not affect anything in the computer.

I can. Funky, off-brand keyboards in particular can be difficult to
configure for.

> I have seen there are a couple of USB devices that work well with
> Windows but not with Linux. I have also seen that the latest
> FC4 kernel update changes a couple of things to make it emulate
> Windows more closely when querying the devices about their
> configuration data. This reportedly helped for some device that
> did not work, but at the expense of others that used to work,
> but no longer do.

Agreed. Mark, can you list the *whole* setup, including models of the
computer, keyboard, mouse, and USB KVM? I assume that you're using entirely
USB devices?

> Does your Linux box see the keyboard etc? Check the /proc/bus/usb/devices
> file. Lines starting "T:" start a new device entry. Expect to see the kvm
> as hub device with the keyboard, mouse and monitor as connected devices.
> The kvm should pretend to each computer (i think) the devices are there
> all the time.

Good advice. I've seen some interesting issues with PS/2 devices where the
PS/2 mouse under Linux would not be usable with a cheap KVM after switching
away from the Linux machine, and the only fix was to switch to using USB,
but USB wouldn't work to talk to the BIOS due to very poor quality BIOS's.

I agree with you that the KVM switch should see the Scroll Lock key
before Linux sees it. The box that I bought the KVM switch in says
that it works with all operating systems. Yes, Linux sees my USB
keyboard and USB mouse just fine. Somehow, the operation of the KVM
switch seems to be affected by Linux. I'm wondering if I should just
return this KVM switch and get a different brand.

On Sun, 30 Oct 2005 02:52:48 +0200, Nico Kadel-Garcia <nkadel@comcast.net> wrote:

>
> "Enrique Perez-Terron" <enrio@online.no> wrote in message
> newsp.szfm1enwnxtvbs@apeiron.home.lan...
>
>> I can't imagine your X server disabling the scroll lock key, I
>> would think that the KVM sees the key events before the computer.
>> The computer only sees them if the kvm forwards them. Disabling the
>> key would only mean the key did not affect anything in the computer.
>
> I can. Funky, off-brand keyboards in particular can be difficult to
> configure for.

If reality exceeds my imagination, it's not particularly sensational .
Do you have any ideas about the mechanism?

However, the difficulties of the kernel probing the devices could have the
side effect of putting the kvm in some unusable state.

-Enrique

On Sun, 30 Oct 2005 02:57:48 +0200, Mark <mkhuebner@gmail.com> wrote:

> I agree with you that the KVM switch should see the Scroll Lock key
> before Linux sees it. The box that I bought the KVM switch in says
> that it works with all operating systems. Yes, Linux sees my USB
> keyboard and USB mouse just fine. Somehow, the operation of the KVM
> switch seems to be affected by Linux. I'm wondering if I should just
> return this KVM switch and get a different brand.

Hey, you can't just do that! Then we don't learn anything!

(But you are probably right.)

It would still be nice if you would post the contents of
/proc/bus/usb/devices, and perhpas some of the data Nico requested too.
Also check dmesg, just in case.

-Enrique

mst wrote:

> On 29 Oct 2005 12:48:51 -0700 "Mark" <mkhuebner@gmail.com> wrote:
>
> > I have a KVM USB 2.0 switch connected to my Thinkpad laptop and my
> > Athlon desktop computer. The KVM Switch is from Cables Unlimited
>
> Yea, I've heard they, uh, suck, for lack of a better term.

I used a usb kvm for awhile and suffered through a number of so-called
lost signals where both systems just blinked like crazy and the
keyboard would not work for either one. Windows or Linux. I went with
an iogear 2 port kvm which is a handy little non-usb one and its worked
remarkably well for me including some nice mouse emulation. I think I
found it at a Fry's for around 49.00 or so. It will only do 2
computers though. The other nice point about it is that it has cables
already attached and you don't need to plug it in. I'm using it on
Debian Linux and XP now; but I've used it with a laptop with a
replicator running XP and a desktop running Debian Linux.

--
Michael Perry | Do or do not. There is no try --Master Yoda
mperry@lnxpowered.org | http://www.lnxpowered.org