Messages in this thread | | | Date | Wed, 13 Dec 2006 13:26:33 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: [GIT PATCH] more Driver core patches for 2.6.19 |
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On Thu, 14 Dec 2006, Benjamin Herrenschmidt wrote: > > Actually, you can... but wether you want is a different story :-) > > You can simply mask it, have it handled by userspace and re-enable it > when that's done.
Nope. Again, this whole mentality is WRONG.
It DOES NOT WORK. No architecture does per-device interrupts portably, which means that you'll always see sharing.
And once you see sharing, you have small "details" like the harddisk interrupt or network interrupt that the user-land driver will depend on.
Oops. Instant deadlock.
> I don't mean I -like- the approach... I just say it can be made to > sort-of work. But I don't see the point.
No. The point really is that it fundamentally _cannot_ work. Not in the real world.
It can only work in some alternate reality where you can always disable interrupts per-device, and even in that alternate reality it would be wrong to use that quoted interrupt handler: not only do you need to disable the irq, you need to have an "acknowledge" phase too
So you'd actually have to fix things _architecturally_, not just add some code to the irq handler.
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