[parisc-linux-cvs] linux-2.6 willy

[Grant Grundler]

On Sun, Jan 02, 2005 at 02:47:43PM -0600, James Bottomley wrote:
> 1) Disable the interrupt routine.  The problem here is that the card
> still asserts the interrupt so we get an unhandled interrupt, which
> causes the kernel to get annoyed and disable the interrupt anyway.

I didn't realize the kernel would eventually shutdown unhandled
interrupts. It's a good idea (ie IRQs left active by BIOS) in any case.

> 2) Disable the interrupt.  Here we've stopped listening to any other
> sharers of this interrupt as well.
> 
> Clearly, the best choice is to beat all the HW vendors up until they
> allow the driver to disable the interrupt on the card.  However, if
> we're reduced to a choice between these evils, I think what linux
> chooses (number 2) is the slightly less evil one.

If it's possible for the kernel to consistently diagnose (1),
I don't see how (2) is less evil. Worst case is now we end up
in the same situation for broken HW.

I consider (2) more evil because it always interfers with 
other devices even when the HW is not broken.
But I'm assuming (1) is "consistently diagnosed" and I'm not
real comfortable yet it's a valid assumption - it's a hard one to prove.

thanks,
grant