Messages in this thread | | | Date | Mon, 21 Jan 2002 18:44:33 +0100 | From | Jens Axboe <> | Subject | Re: Linux 2.5.3-pre1-aia1 |
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On Mon, Jan 21 2002, Andre Hedrick wrote: > > I always thought it is like this (and this is what I still believe after > > having read the sprcification): > > > > --- > > SET_MUTIPLE 16 sectors > > --- > > READ_MULTIPLE 24 sectors > > IRQ > > PIO transfer 16 sectors > > IRQ > > PIO transfer 8 sectors > > --- > > > > Where am I wrong? > > > > By the way, the device *isn't* required to support any lower multiple > > count than the maximum one it advertizes. Ugly. > > No but the HOST is to obey the requirements of the device. > The spec is written from the drive side not the host side. > > "All Ye Hosts, SHALL address me in such a manner as described, or be > aborted or I SHALL remain in an undertermined state." > > Note only recently have the HOSTS been about to setup guidelines for what > is sane and not stupid for the device to do or behave. > > Again, the HOST(Linux) is not following the device side rules so expect > difficulty when we depart. The Brain Damage is how to talk to the > hardware, and it is clear we are not doing it right because we are bending > the rules stuff it into and API that not acceptable. However we are > stuck. Again, simplicity works, generate a MEMPOOL for PIO such that the > buffer pages are contigious and the 4k page dance is a NOOP. Until that > time we will be fussing about.
Andre,
Do you know how to say "I was wrong"? You are walking off-track again. It's clearly the way that Vojtech and I describe, otherwise current code would just not work. And 2.4, 2.2, 2.0 neither.
-- Jens Axboe
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