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SubjectRe: libata git tree, mbox queue status and contents
Alan Cox wrote:

>>* Alan: IORDY handling -- upstream whenever Alan is happy

> I'm happy with it from testing. Just a little worried about it going
> upstream mid -rc as it could have a weird side effect somewhere. I've
> verified an original pre ATA IDE drive with it too now 8)

>>* Alan: ACPI checks for 80wire cable -- upstream whenever Alan is happy

> Happy

>>* Albert: irq_on/off. Really need to give this some thought. Not sure
>>I like where this model is going. Polling and twiddling irq on/off
>>should be kept to a minimum, because it's sorta an admission that the
>>host state machine has broken down, and we need to bandaid. Its a
>>bandaid not a root-cause solution.

> I think of it more as an admission that the IDE design is lacking in a
> few areas. No suprise as its an emulation of a 15 year old interface that
> was normally used polled.

Hehe, note that even host polling has always been racy the way ATA spec.
described it: there was noting said about the period whithin which the device
should assert INTRQ after clearing BSY (and the interrupt-pending state wasn't
clearly specified also), so there's a possibility for the fast host to *not*
clear interrupt pending by reading the status reg. with BSY=0 but before the
devie enters interrupt-pending state, and thus possibly stalling the further
transfer.

MBR, Sergei
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