kvm question

A home for those technical problems.

kvm question

Postby Lairiodd » Tue Apr 10, 2007 1:45 pm

I am trying to use a kvm (usb) switch to switch between a laptop and a linux desktop. It works for a few switches and then it crashes the linux box (though sometimes the Linux box can still be telnetted into).

Anyone have any experience using them ?
Prydwen
Lairiodd Level 50 Nightshade and Legendary Grandmaster Smith (1065) check prices here
Lairirian Level 50 Mana Mentalist and Legendary Spellcrafter (TDD)
Lairgreybark Level 50 Arb Animist
Lairmindlock Level 50 Bard (TDD)
Camlann
Lairthall Level 35+ Friar

Stocking one 99% of most of the useful spellcrafting gems at Houses 3304 and 3306

Over 150 gems at 99% stocked
Lairiodd
Savant
 
Posts: 1688
Joined: Sat Feb 05, 2005 12:00 pm

Postby Xest » Tue Apr 10, 2007 1:51 pm

I have some experience, is both the keyboard and the mouse USB or is the keyboard PS/2?

Is the KVM switched powered or does it draw power via USB/PS/2?
OFFICER XEST - PROTECTING YOU AGAINST FORUM CRIME
Image
Che Xefan, el presidente.
Xest
Savant
 
Posts: 3022
Joined: Mon Feb 07, 2005 12:00 pm

Postby Lairiodd » Tue Apr 10, 2007 8:10 pm

It is all USB. In fact, there is no specific connections to plug the keyboard and mouse into, they can be connected to any usb port on the 'front'. I think it may be a usb-hub switch. (though presumably with some kind of keyboard/mouse emulation).

The 'back' of the switch has 2 usb connectors that connect to a usb port on each computer, so the keyboard/mouse shares that connection.

The model is sitecom kv-010.

It has a power supply, but it doesn't seem to make any difference if it is powered up.

What seems to be happening is that the usb mouse/keyboard drivers for the Linux box are crashing. If they could be reset somehow, then it would be less unreliable. It does sometimes crash the Linux box outright though. However, finding why it is crashing the usb driver might fix everything.

The sysadmin found that if you boot up with the keyboard/mouse connected directly to the Linux box, and the switch them to the switch, it is more reliable (in that it doesn't die on the first switch to the Linux box).
Prydwen
Lairiodd Level 50 Nightshade and Legendary Grandmaster Smith (1065) check prices here
Lairirian Level 50 Mana Mentalist and Legendary Spellcrafter (TDD)
Lairgreybark Level 50 Arb Animist
Lairmindlock Level 50 Bard (TDD)
Camlann
Lairthall Level 35+ Friar

Stocking one 99% of most of the useful spellcrafting gems at Houses 3304 and 3306

Over 150 gems at 99% stocked
Lairiodd
Savant
 
Posts: 1688
Joined: Sat Feb 05, 2005 12:00 pm

Postby Xest » Tue Apr 10, 2007 9:47 pm

Tried different mouse/keyboard combos just to rule out that it's not something daft to do with certain hardware?

I've usually used PS/2 KVMs in the past and they were always problematic, although it was often fairly easy to fix by ensuring power to the KVM if it needed it or a couple of registry hacks for Windows boxes that couldn't detect the PS/2 devices again after switching away.

I'm not sure how reliable two devices sending data via one USB connection is (although this is part of the USB spec so it should be catered for) and it does indeed sound like it's just crashing the USB stack or some such. You can easily restart modules in Linux such as networking and so forth but I don't know offhand what the USB stack falls under (input?) and hence the exact command to restart it.
OFFICER XEST - PROTECTING YOU AGAINST FORUM CRIME
Image
Che Xefan, el presidente.
Xest
Savant
 
Posts: 3022
Joined: Mon Feb 07, 2005 12:00 pm

Postby Lairiodd » Wed Apr 11, 2007 12:07 am

Another issue is that I only have user rights on the Linux box. A restart would likely require root.

Windows has no problem re-locking to the mouse/keyboard, which doesn't say much for open source :p.
Prydwen
Lairiodd Level 50 Nightshade and Legendary Grandmaster Smith (1065) check prices here
Lairirian Level 50 Mana Mentalist and Legendary Spellcrafter (TDD)
Lairgreybark Level 50 Arb Animist
Lairmindlock Level 50 Bard (TDD)
Camlann
Lairthall Level 35+ Friar

Stocking one 99% of most of the useful spellcrafting gems at Houses 3304 and 3306

Over 150 gems at 99% stocked
Lairiodd
Savant
 
Posts: 1688
Joined: Sat Feb 05, 2005 12:00 pm

Postby Lairiodd » Wed Apr 11, 2007 12:08 am

I guess I could try with another mouse/keyboard.
Prydwen
Lairiodd Level 50 Nightshade and Legendary Grandmaster Smith (1065) check prices here
Lairirian Level 50 Mana Mentalist and Legendary Spellcrafter (TDD)
Lairgreybark Level 50 Arb Animist
Lairmindlock Level 50 Bard (TDD)
Camlann
Lairthall Level 35+ Friar

Stocking one 99% of most of the useful spellcrafting gems at Houses 3304 and 3306

Over 150 gems at 99% stocked
Lairiodd
Savant
 
Posts: 1688
Joined: Sat Feb 05, 2005 12:00 pm

Postby Xest » Wed Apr 11, 2007 12:28 am

Lairiodd wrote:Another issue is that I only have user rights on the Linux box. A restart would likely require root.

Windows has no problem re-locking to the mouse/keyboard, which doesn't say much for open source :p.

Well that's the problem with Linux, frankly, driver support is utter crap.

As much as I love the stability of a Linux server if it happens to fully support the hardware it's running on, if you try and build a system using hardware that doesn't come with Linux drivers (which is the majority of hardware) then you're going to run into problems - until the open source community fixes that, Linux isn't ever going to achieve mainstream.

You're right that restarting input/USB services would require a root or at least superuser privalages, if you can't su it's probably not an option. How old is the kernel in the system in question?
OFFICER XEST - PROTECTING YOU AGAINST FORUM CRIME
Image
Che Xefan, el presidente.
Xest
Savant
 
Posts: 3022
Joined: Mon Feb 07, 2005 12:00 pm

Postby Lairiodd » Wed Apr 11, 2007 8:35 am

Think its 2.4

Anyway, with a new keyboard, and it switched 5 times without crashing, though that may just be luck.
Prydwen
Lairiodd Level 50 Nightshade and Legendary Grandmaster Smith (1065) check prices here
Lairirian Level 50 Mana Mentalist and Legendary Spellcrafter (TDD)
Lairgreybark Level 50 Arb Animist
Lairmindlock Level 50 Bard (TDD)
Camlann
Lairthall Level 35+ Friar

Stocking one 99% of most of the useful spellcrafting gems at Houses 3304 and 3306

Over 150 gems at 99% stocked
Lairiodd
Savant
 
Posts: 1688
Joined: Sat Feb 05, 2005 12:00 pm


Return to Tech Help

Who is online

Users browsing this forum: No registered users and 1 guest

cron