Messages in this thread | | | Subject | Re: [PATCH] libata-sff: Don't call bmdma_stop on non DMA capable controllers | From | David Woodhouse <> | Date | Fri, 26 Jan 2007 13:09:40 +0800 |
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On Thu, 2007-01-25 at 20:48 -0800, Linus Torvalds wrote: > Irq0 may _exist_. IO Port 0 may _exist_. Virtual address 0 may > _exist_. > > Got it? > > But they ARE NOT VALID THINGS FOR DRIVERS TO WORRY ABOUT.
I do understand what you're saying; there's no need to shout. I think it's very misguided and leads to both internal inconsistency (as demonstrated by the setup_irq() patch) and external inconsistency with stuff like hardware documentation. But I _do_ understand what you're saying.
> When a *DRIVER* sees a [zero], it's always a sign of "not here".
Except when it isn't. Like when it's a DMA address. Or a file descriptor. Or a CPU number. Or one of numerous other things.
But still, I do understand what you're saying although I disagree with your intention and your statement above is plain wrong (well, at least my misquote of it is wrong -- you actually said 'NULL' which is fair enough, but in the middle of a rant about _zero_ so I edited the quote to say zero because that's what we're actually talking about).
> But they ARE NOT VALID THINGS FOR DRIVERS TO WORRY ABOUT. ... > NO NORMAL USER SHOULD EVER SEE [zero] AS A REAL IO PORT.
Yes, that much I understand. We disagree, but I understand you. My last response was not intending to pursue that part of the discussion.
My question was about _how_ you think this should be achieved in this particular case. You didn't like the suggestion that we should put your new special-case hack into the resource code... where/how _do_ you suggest that it's done, so that we can protect those poor driver authors from the number zero?
-- dwmw2
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