Assign interrupt to USB Host Controller?

[Brad Jones]

Hello,
I'm working in a commercial OEM environment and believe there's an interrupt
issue between a specific bus driver (VME) and a USB network adapter. I know
the two devices should be able to safely share the interrupt but I'm getting
some strange behavior. When letting the system (Windows 2000) choose the
settings, the two devices end up on the same interrupt. To verify that this
might be the problem, I'd like to force the "Intel 82371AB/EB PCI to USB
Universal Host Controller" to use a specific interrupt. Due to the system
design, the bus driver IRQ cannot change and configuration of the IRQ isn't
an available Device Manager option for the USB controller. Does anyone have
any suggestions or advice? Thanks in advance.

- Brad

 

[Rick]

Hello,
I'm working in a commercial OEM environment and believe there's an interrupt
issue between a specific bus driver (VME) and a USB network adapter. I know
the two devices should be able to safely share the interrupt but I'm getting
some strange behavior. When letting the system (Windows 2000) choose the
settings, the two devices end up on the same interrupt. To verify that this
might be the problem, I'd like to force the "Intel 82371AB/EB PCI to USB
Universal Host Controller" to use a specific interrupt. Due to the system
design, the bus driver IRQ cannot change and configuration of the IRQ isn't
an available Device Manager option for the USB controller. Does anyone have
any suggestions or advice? Thanks in advance.

If ACPI is enabled you don't have manual control over IRQs.
Does the system bios have an option to disable ACPI support?
If so, reinstalling Win2K without ACPI support would be one
workaround.

Rick

 

[Brad Jones]

Rick, thanks for taking the time to reply.
There's no ACPI support in the BIOS (Phoenix), only some APM, and that is
always disabled. Also, the computer is configured as "Standard PC" and I
think this changes to something else (ie, "MPC PC") with ACPI enabled. I
also turned off IRQ steering from within Device Manager but the two devices
are still sharing the same IRQ.

I'm working under the assumption that unless the driver supports manual
configuration then the option to "Configure Manually" is disabled in Device
Manager. I guess I'll keep hacking at it for a workaround. Thanks for the
ACPI advice, I didn't know that, and it's something I'll need to look out
for in the future if the BIOS is updated.

Regards,
Brad

 

[Rick]

Rick, thanks for taking the time to reply.
There's no ACPI support in the BIOS (Phoenix), only some APM, and that is
always disabled. Also, the computer is configured as "Standard PC" and I
think this changes to something else (ie, "MPC PC") with ACPI enabled. I
also turned off IRQ steering from within Device Manager but the two devices
are still sharing the same IRQ.

I'm working under the assumption that unless the driver supports manual
configuration then the option to "Configure Manually" is disabled in Device
Manager.

Not quite true.. IRQ assignments are hardwired into motherboards
(e.g. AGP and PCI slot 1 often share an IRQ), and Windows
simply picks up this arrangement from the hardware.

Rick