RE: The buggy APIC of the Abit BP6

["Robbert Kouprie" <robbert@radium.jvb.tudelft.nl>]

Helge Hafting wrote:

> > Jun 12 23:47:56 radium kernel: unexpected IRQ trap at vector 7d
> > Jun 12 23:47:56 radium kernel: unexpected IRQ trap at vector 7d
> 
> It _can_ be solved - rebooting cures it, so assuming the problem
> is autodetectable it _can_ be solved by doing whatever it is
> a reboot (or driver reload) does to the APIC.

True.

> My guess is that the APIC setup for that IRQ have to be reprogrammed.
> you could do that as a quirk for the BP6.
> The first question is if there is a reliable way to detect this
> condition.  "No interrupts from a device" could simply mean that
> it isn't used much at the time.  You get a unexpected IRQ trap - do
> the problem always manifest itself this way?

Yes, I always get the "unexpected IRQ trap at vector 7d" message. This
is the same message even with different NICs (though they were placed in
the same PCI slot). About 30-120 seconds after this message (depending
on some driver timeout value I guess) the NETDEV watchdog kicks in with
a "eth0: transmit timed out".

> The second question is if all the PCI card drivers out there
> survive a lost interrupt handled outside the driver.  
> If not, you have to close+reopen the device, and that involves
> userspace.
> A network card will need reinitialization, a disk controller
> remounting...

That could indeed be a problem. But this will become clear pretty soon
once this APIC reprogramming workaround is actually implemented in the
kernel. Then I will be able to test that. Any ideas how this workaround
in the kernel would look like?

Thanks for the help,
- Robbert Kouprie