Re: pcmcia oops on 2.6.17-rc[12]

From: Rogier Wolff
Date: Mon May 22 2006 - 17:26:52 EST

On Mon, May 22, 2006 at 01:10:04PM +0100, Alan Cox wrote:
> On Llu, 2006-05-22 at 13:50 +0200, Rogier Wolff wrote:
> > I happen to know (ISA) hardware that CANNOT share an interrupt: It
> > drives the IRQ line either high or low, and has a driver that will
> You happen to be wrong. Some ISA boards use the correct diodes and
> pulldowns and can share an IRQ line although being edge triggered you
> must take great care to get it right.

I feel like I'm repeating myself... I happen to know (ISA) hardware
that /cannot/ share an interrupt. It does /not/ use correct diodes and
pulldowns. I have equipped the driver with the knowledge that it
cannot share the interrupt.

Linus' sugesstion that as an intermediate measure request that
everybody explictly flag: shared is ok, or "NO WAY", sounds like a
plan. In the meanwhile the infrastructure may warn about that driver
so that some human thinks about it, and adds the right flag. Only after
a while, (when there is no longer anybody using the default) can we
change the default....

Alan and Linus know (ISA) hardware that /can/ share interrupts.
Fine. I know hardware that /cannot/ share interrupts. So, my driver
requesting an interrupt, and getting: "Can't allocate interrupt" is an
indication of a hardware configuration error. Or software (you've been
telling one of the drivers the wrong interrupt line). If you force
"shared mode", my driver will cope (it works just great on the PCI
version of the card, no problem). But will the hardware?

You guys maybe trying to fix very real problems in PCMCIA land, of
which I have very little knowledge. But changing what "not passing
SA_SHIRQ" means globlaly IMHO changes too much...


** R.E.Wolff@xxxxxxxxxxxx ** ** +31-15-2600998 **
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