USB controller error -71

[Petcan]

Hi,
I have a KVM hub to share keyboard and mouse between Red Hat workstation and a Windows workstation.
At apparently random intervals /var/log/messages records the error
usb2-4:device not accepting address AA, error -71

From this point on it is not possible to connect keyboard and mouse.
The only way I know to recover is a system reboot.

Does anyone know what could be triggering the error and is there an easier way to recover?

Thanks in advance.

[Rubberman]

For the switch to work properly, it should be "live" as far as each system connected to it is concerned, so they think that your keyboard and mouse are still attached, even if you are connected to one of the other systems on the KVM. So, it is possible that the KVM has developed a fault, or has a design flaw. Have you tried another KVM?

[Petcan]

For the switch to work properly, it should be "live" as far as each system connected to it is concerned, so they think that your keyboard and mouse are still attached, even if you are connected to one of the other systems on the KVM. So, it is possible that the KVM has developed a fault, or has a design flaw. Have you tried another KVM?

I can see that each time I select the Windows system that the keyboard and mouse devices are disconnected by the USB controller.
From your reply I gather that a 'good' KVM will maintain the USB assignment even when the alternate system is selected. Correct?
I was hoping to avoid changing hardware as I have the same hardware setup repeated over 30 times.
Is there an easy way to reset the USB controller, maybe by restarting a daemon or something like that?

[Rubberman]

Normally the system should see that the devices are plugged in after you switch KVM ports, though it may take a little time. Also, have you tried replugging the keyboard and mouse into the kvm after you switch it back to the Linux host? Anyway, I was using a d-link kvm for quite awhile and never ran into this issue, which is why I am thinking that there may be an issue with the kvm. Have you tried another one of the same model to see?

[Petcan]

It's not a problem with the individual device. I have it occurring on several workstations with the same model KVM. Replugging devices doesn't clear the problem, nor does power cycling the KVM.
I believe that there are different USB drivers in Red Hat. I don't suppose you know if there are any significant differences between available drivers?

[Rubberman]

It's not a problem with the individual device. I have it occurring on several workstations with the same model KVM. Replugging devices doesn't clear the problem, nor does power cycling the KVM.
I believe that there are different USB drivers in Red Hat. I don't suppose you know if there are any significant differences between available drivers?

What version of RHEL are you running, and what kernel (output of "uname -r")? Also, are some of the Linux workstations working ok with these KVM switches? If so, please post their distribution+version+kernel info as well.

[Petcan]

I'm running RHEL4, kernel 2.6.9-89.0.11.ELsmp.
All my workstations are running the same version.
I have some workstations that have never experienced a problem but I am not confident that they will not have it in the future.
I have managed to trigger the error by toggling the KVM at high frequency but I cannot do it systematically. I am confident that this is not what is happening when I get the failures in the normal operating scenario. I was hoping that some expert knowledge regarding the USB controller error might help identify the trigger for the error.