Messages in this thread | | | Date | Thu, 6 Dec 2001 12:59:35 +0300 | From | Ivan Kokshaysky <> | Subject | Re: IDE DMA on AXP & barriers |
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On Thu, Dec 06, 2001 at 06:13:15AM +0100, Kurt Garloff wrote: > I would imagine that the following barriers are nacessary: > * After setting up the IDE DMA tables (PRD) and having the data there, > we need to have a barrier before telling the controller to do DMA.
Actually, we have more than one - the memory barriers are hidden in outX() macros.
> * After the controller is done with it, we need to make sure the > data is in mem before we use it (i.e. we need some mb() equiv on the > controller)
Sure, otherwise the controller just wouldn't work, and not only on alpha. I never had any problems with IDE DMA on lx164 (which has exactly the same IDE chip), but it was back in 2.3 or 2.4-test times... Maybe something got broken since then - I could check this (if I find a spare IDE drive).
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