Re: [PROBLEM] xircom CBE2-100(faulty) hangs kernel 2.4.{21, 22-pre8} (fwd)

[David Hinds <dhinds@sonic.net>]

On Wed, Aug 06, 2003 at 03:55:02PM -0500, Hmamouche, Youssef wrote:
> 
> I'm a user. When I insert a card "into my laptop" I'd like it to
> work as advertised. If it doesn't work as advertised(because of some
> hardware failure in this case), I'd like the kernel to more or less
> let me know that something went wrong so I can return it. I wouldn't
> expect the kernel to freeze.

I accept this...

> Faulty hardware is very common in the PC era. I agree that it is
> hard to pin down hardware malfunctions when you don't know what to
> check for. However, There should be concern when it takes your whole
> system down.

I'd agree, that drivers should be made to not screw up when an
unexpected condition arises, where that's possible.  Like, not
crashing the OS if a device returns an unexpected value.

This particular problem (what seems to be an unacknowledged interrupt,
but that could be a symptom of something else) is troublesome and
likely impossible for the driver to detect and handle sanely.  Because
PCI interrupts are shared, and a driver cannot assume that its device
was responsible for any particular interrupt.

I believe that the 2.6 kernel provides a general central mechanism for
detecting and throttling unacknowledged interrupts, if that really is
the problem.  That's where this particular fix belongs, not in the
driver (and every other driver).

-- Dave