Linux and KVMs

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Linux and KVMs

Postby TheDoctor » Wed Jan 11, 2006 3:12 pm

I've just installed openSUSE from the Linux Format disks - and it worked just fine, so no problem there.

However, I have more than one PC and I access them via a Belkin KVM. The Linux machine is perfectly happy being accessed this way, as long as I don't switch away from it and switch back. When I switch back, the mouse goes crazy, shooting all over the place, selecting random options, etc.

Searching the web, I found that this is a common problem when using Linux in combination with a Belkin KVM. I also found an explanation (http://www.linuxquestions.org/questions/showthread.php?postid=778557#post778557) which put the blame firmly in the hands of the 2.6 Kernel.

The writer of that post (almost two years old) suggested that work was being done to solve the problem. Anyone know of a fix available anywhere?

The other, more expensive option, is to buy (aargh!) a new KVM. Suggestions as to ones that I can happily switch between Windows and Linux are also welcome.

The short-term workround is, of course, to connect a two-button mouse to the Linux machine instead of the KVW mouse connection, but this is obviously not an acceptable long-term solution.
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RE: Linux and KVMs

Postby jdtate101 » Wed Jan 11, 2006 4:37 pm

Strange..I use suse10 and a belkin KVM with no issues.
Which model KVM are you using..I'm on the two port USB model with intergrated cables (ie cheap option)
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Postby TheDoctor » Wed Jan 11, 2006 5:17 pm

I'm using a 4-port omniview. The omniview is the one that there seems to be the most complaints about. Try goggling for "belkin kvm linux" (without the quote marks) to get a flavour of the problem.

Curiously enough, someone posted on another forum a couple of days ago (found soon after I posed here) and it was suggested that he amend etc/x11/xorg.conf so that his mouse protocal was set to "auto". It apparently worked for him but not for me. (I've also tried "IMPS/2", which is another suggestion I found, with similar lack of success.)
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Postby spottedcat » Fri Jan 13, 2006 12:18 pm

I'm using a Belkin KVM 4-way switch with a Microsoft (sorry!) optical 2-button +wheel USB mouse connected to the switch with a PS2/USB adapter. I've just tried switching between Windows and Suse 10, and then Windows and Suse 9.3, and encountered no problems. Even the scroll wheel worked as it should. I'd tell you the Belkin model if I could lift it up and read the underside without all the connections falling out, but I can't. Perhaps the problem lies in the particular version of the 2.6 kernel. Have you checked for updates?
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Postby MGE » Sun Jan 22, 2006 1:48 am

I had the exact same problem, using a belkin kvm hub (2 port).
Everytime I switched from one PC to another the mouse went nuts.

However, as soon as I stopped using a PS/2 kvm and used a USB one, the problem
went away.
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Postby TheDoctor » Mon Jan 23, 2006 12:02 am

Thanks for the replies over the last week or so. Sorry I haven't responded sooner.

Spottedcat: I read a post on another forum that argued the problem was with the kernel, but that was posted back in 2004. Part of the reason for my post was to see if anyone would tell me to install this or that update. But I think the problem has not been solved.

MGE: I've read elsewhere that connecting the mouse via USB solves the problem, so I think I'll try that. Thanks for confirming that it works.

(Mind you, I've seen someone say that changing the mouse model to "auto" works for them, but it doesn't work for me, so I suppose I'll have to see. :) )
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Postby TheDoctor » Thu Jan 26, 2006 2:16 pm

A last update: I got myself a PS/2 to USB converter, so my mouse and keyboard now connect to my Linux machine through USB. This has solved the problem.

As I understand it, Belkin KVMs send out extraneous characters which the kernel will handle from a PS/2 conection just so long as you don't switch to another machine. However, if you connect a mouse via a USB the kernel knows to ignore these characters come what may.

All I need now to be perfectly happy is a Linux driver for my mouse so I can use its wheel! So off I go to search the web....
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Postby spottedcat » Thu Jan 26, 2006 4:30 pm

TheDoctor wrote:A last update: I got myself a PS/2 to USB converter, so my mouse and keyboard now connect to my Linux machine through USB. This has solved the problem.

As I understand it, Belkin KVMs send out extraneous characters which the kernel will handle from a PS/2 conection just so long as you don't switch to another machine. However, if you connect a mouse via a USB the kernel knows to ignore these characters come what may.


- which is curious because my Belkin KVM is a PS2 version, and I don't get your problem. My USB mouse is connected to the PS2 socket of the KVM switch via a USB to PS2 converter - the opposite of yours.

Anyway, glad to hear it's sorted.
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Postby towy71 » Thu Jan 26, 2006 6:44 pm

TheDoctor wrote:..8<..
All I need now to be perfectly happy is a Linux driver for my mouse so I can use its wheel! So off I go to search the web....

the scroll is controlled by the xserver and to get it to work you need to edit the /etc/X11/xorg.conf so the section is laid out so:
Code: Select all
Section "InputDevice"
   Identifier   "Configured Mouse"
   Driver      "mouse"
   Option      "CorePointer"
   Option      "Device"      "/dev/input/mice"
   Option      "Protocol"      "ImPS/2"
   Option      "ZAxisMapping"      "4 5"
EndSection


HTH
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Postby TheDoctor » Thu Jan 26, 2006 7:09 pm

Thanks Towy71. :D I tried doing what you said and now I can't get Gnome started. It says there's a configuration problem with the X server.

I'll try rebooting from CD when I have a few moments.
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Postby towy71 » Fri Jan 27, 2006 10:10 am

whoops!
login to boot screen and type sax2, this should help you fix the xorg.conf via its own server
its probably the because I just copied from my ubuntu config file the Suse config file should read:
Code: Select all
Section "InputDevice"
   Identifier   "Mouse[1]"
   Driver      "mouse"
   Option      "Device"      "/dev/input/mice"
   Option      "Protocol"      "explorerps/2"
   Option      "ZAxisMapping"      "4 5"
EndSection

sorry about that
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Postby antihippy » Fri Feb 03, 2006 12:01 pm

Hii,

I get a similar problem - albeit with the monitor.

I am currently playing with an Ubuntu box as a possible client on my network (which is currently a MS AD domain). I have the ubuntu box attached to a Belkin 2 port USB KVM switch. When I use my MS Laptop all is well; when I swtich to the ubuntu box the screen seems to be 'blinking'. The monitor in question is a Dell 15" LCD monitor. When it is attached directly to the Linux box it is ok. If you put it through the switch then the blinking starts as soon as you switch over. In fact if you keep watching the screen the blinking gets faster until it screen goes on and off every 1/2s or so. Can anyone give me an idea what might be causing it?
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Postby spottedcat » Fri Feb 03, 2006 1:04 pm

Can't answer that, antihippy, but I have noticed one oddity around the monitor with my 4-way Belkin KVM which may be relevant. Several times I had reset the refresh rate on a Windows box to 72 only to find that it had reset itself to 60 in my absence. I know Window$ has a mind (!?!) of its own, but really... Then Ubuntu did something odd, booting up into a ridiculous resolution - 640x480. My monitor supports 1280x1024. That's when I realised what I'd done wrong. I had been booting the Windows machine and then the Ubuntu one with the KVM switched to another machine. I presume that without a monitor to talk to directly, both Windows and Ubuntu get confused. Now, if I want to have more than one machine running, I switch the KVM first, then boot up.

Unless, that is, someone else has a better explanation.....
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Postby photobod » Sun Feb 05, 2006 2:33 pm

Don't know about Belin KVMs, but I've used the ones cheap, own-branded ones provided by eBuyer in several setups with no hassles at all. These are so cheap that you might consider it worth swapping just to avoid the problems.
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Postby TheDoctor » Tue Feb 07, 2006 9:14 pm

TheDoctor wrote:A last update: I got myself a PS/2 to USB converter, so my mouse and keyboard now connect to my Linux machine through USB. This has solved the problem.


I wish. It stopped working altogether (froze when I switched to the Windows machine and back), so I tried the change that Towy71 suggested and, as I said, my Linux PC stopped working altogether. I've now followed Towy71's instructions to recover and got my machine back!

However, the mouse still wasn't behaving itself and stopped working entirely via the USB. The keyboard also stopped working via the USB if the mouse was connected. However, I decided it wasn't a Linux problem when the mouse froze on the Windows PC!

I've now removed the offending mouse (a Belkin wireless optical mouse with a beautiful light touch) and connected an old Microsoft mouse (with ball and wire). This works, although the wheel feels stiff and rusty compared to the Belkin one. But better a mouse wheel that's stiff and works than a mouse wheel that's light but does nothing.

Thanks for everyone's help. The Linux PC is currently just a plaything, so there's no problem for me if things don't work perfectly just yet, provided I keep on the learning curve.

On that last point, where can I find out about the xserver?
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