problem booting with KVM switch
 

Hi,

I've got several computers running through the same mouse,keyboard, and monitor using a Linksys KVM switch. This has been great, in that I have a lot more desk space than I did when I had three monitors, keyboards and mice running around on it.

However, there's one problem. Occasionally, everything gets turned off (power failure's a couple times, and most recently a guest staying in the room with the computers). When I power the computers back up, any linux machine that can't see the mouse (and by definition only one can at most), doesn't have a mouse, and the logon screen comes up mouseless.

What I've had to do is reboot them one at a time, switching the KVM switch to the corresponding computer until it has scanned past the mouse detection part.

Is there a way to to tell linux not to scan for the mouse? That it already knows what kind of mouse is attached, whether it can see it at the moment or not?

Thanks.

jcunningham

I have a Linksys KVM and my linux box (RH 7.2, P233, Supermicro MB) doesn't exhibit the problem you described. However, my Thinkpad iSeries 1700 does. I'm curious if anybody has solved this problem for a Thinkpad out there?

Really?! You mean that if you power up your linux box with the KVM switch switched to somewhere other than your linux box, that you have a mouse after its booted?

I know another guy who runs RH 7.2 into a Netgear KVM switch and he has the same problem I do.

I think the problem is kudzu isn't finding a mouse when it scans for one. I'm just trying to figure out if there's a way to tell it "don't worry about it - you've got one, alright?".

I use a separate mouse for each system. I have the same problem and that's how I got around it. Also had a similar experience with nt 4.0 It would not find the mouse on the kvm switch either.

Win2k is even worse: it not only doesn't find the mouse, but it boots to 640x480 16 color video - by the time you reboot it all your desktop icons are piled up along one side.

A separate mouse isn't a bad idea. They don't take up much space. Thanks.

I have a linksys 2 port KVM switch with a Red Hat 7.3 and XP machine. When I boot linux up with the KVM set to the XP machine it has no problem detecting the mouse. I think you might be having a bios issue and not a linux one.

I know this is not what you're asking for, but some KVM switches emulate mouses for all computers during boot.

-Mike

kvm switch
 

yup mine works with windows 98 but it does not work with nt 4.0 or linux.

Hey, at work I have a Belkin KVM switch connecting WinNT, Win2K and linux box, whenever windows machines are losing network connectivity (happens overnight) I can't bring linux box up (only hard reboot after a couple of attempts brings the linux back up), I am constantely connecting to it through SSH (the box is in another office), and whenever it happens my SSH session hangs as well. I talked to the other end, to get the linux box off KVM and I can't believe people can be that lazy. Oh well, they are receiving a phone call from one of our help desk rep to reboot linux box - if it works for them fine, I might just telnet into it for revenge.

I have the exact same setup as ChaosX2 does, and I have not had any issues with it at all, no problems. Maybe it is a bios issue.. could be ..

Okay, I'm willing to consider the bios thing. On any pc I've ever worked on, if you don't have a keyboard plugged in when the bios scans for it, you don't ever have a keyboard. So, presumably, if the KVM switch connecting anything to the machine being booted, then the bios can't see the keyboard and it should be in trouble, but that's not the problem. Similarly, I can boot a normal pc with the monitor turned off, then later turn on the monitor and the video is in the same mode it was when I shut it off. Again, no problem.

Now, look at the symptoms with the KVM switch. First of all, its not a keyboard problem, but a mouse and video problem. As far as I know, the bios doesn't even scan for a mouse. It can't be a bios issue.

What clearly seems to be happening is that SuSE 8.0 needs to check something about the mouse at some point in the boot, or it won't think it has a mouse. Win2k doesn't care about the mouse, but - like SuSE 8.0 - it does care about the monitor. If the monitor isn't connected (i.e. switched elsewhere) it comes up in 640 x 480 x 16 color mode.

What is more likely is that the difference is in the Belkin switches you guys are using and the Linksys switch I'm using. Maybe the Belkin provides a different kind of termination to the "off"-switched boxes which allows them to identify what would be there where they switched "on".

Just a thought.
I still think there ought to be a way to tell the kernel not to try to identify certain pieces of hardware, but read it from configuration files ("trust me, its there").

J. Cunningham

Jeff

True, my Belkin does emulate devices for me, but because I use a USB mouse and USB isn't loaded yet, I still have to use another mouse for my Linux box. I'm not sure how my winME box knows it'll have a keyboard and mouse to use...maybe I've got USB enabled in the BIOS?

-Mike

4 port Belkin..

I have to unplug my mouse when I switch from Win2K to RH7.3. I have a logitech optical wheel mouse and it cause things to go crazy on my desktop if I don't unplug it. If I reconfig the mouse to not use the scroll things work fine. I find it a little annoying but not as annoying as Win2K...

I'm just trying to undertsand this post, needamiracle. Are you saying that with both computers fully booted, you cannot switch between them without unplugging your mouse from the KVM? Or is this just during boot? If it's just during boot, is your mouse USB? My 4-port supports mouse emulation...doesn't yours?

-Mike

Yes, the only glitch I have is switching between machines...that is when the things go haywire in my window manager. Switching from RH to W2K is fine, everything boots fine as well. The only annoyance is having to unplug the mouse. I have a USB to PS2 adapter on the front of the switch. If I hotkey to any of the machines (scroll lock, scroll lock, then 1-4) things also go wacky. The only real solution that I have found when switching is to unplug then plug in the mouse once I am in KDE. As long as it works I am content... KVMs are great but I wish there was a white paper on making low cost HEADLESS machines with just an ethernet adapter in it. I know you can set the consol output to a serial port, can you set it to an ethernet interface too? The webservers and db servers I run don't need a monitor or keyboard as long as I can SSH to them. I guess another little project can be added to the things I'd like to do with Linux.