Re: VM86 interrupt emulation breakage and FIXes for 2.6.x kernel series

Alan Cox
2004-12-11T19:51:21Z

On Sad, 2004-12-11 at 18:45, Linus Torvalds wrote:
> The interpreter idea is somewhat interesting, especially if the "language"
> can be actually "compiled" into some threaded format or similar. I suspect
> that a number of special devices that you don't want to maintain a
> real kernel module for could be handled that way.

The example I gave is sufficient for vblank on every video card that was
looked at (which is the main X interest for the Xsync extensions). You
also only have to turn the descriptor from "type, size" into function
pointer to get good performance .. at least I think that will be the
case

if((op->func(op->offset) & op->mask) != op->value)
return IRQ_NONE;

> However, I also suspect that such a thing would eventually explode with
> special cases and support for new features people want, to the point
> where it gets quite complex, and a kernel module might be easier after all ;)

For some devices most definitely. The simple descriptors unfortunately
will degenerate into ACPI otherwise.

Alan