Messages in this thread | | | Date | Fri, 26 Jul 2002 02:34:04 +0200 | From | Marcin Dalecki <> | Subject | Re: Safety of IRQ during i/o |
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Bill Davidsen wrote: > On 25 Jul 2002, Alan Cox wrote: > > >>There are also some older systems where if the block transfer of the IDE >>data didn't keep up with the controller instead of handshaking properly >>it kind of dribbled random numbers onto the disk. >> >>Unless anyone knows of PCI era devices with this problem I would be >>inclined to agree that we should default to IRQ unmasking in the 2.5 IDE >>code if the IDE controller is PCI. > > > Certainly if the controller is running in DMA mode. If running in PIO mode > I would think you could still have a problem if the transfer was stopped > mid-block. Perhaps I'm paranoid, is that a "can't happen" now?
Please note that with the advent of on target device caching this is neraly impossible unless you chook the cabling - which is of course something we can't prevent.
>>For old ISA/VLB controllers its safer left as is, and nobody running a >>machine like that can realistically expect good performance without hand >>tuning stuff anyway > > > I would think the guts of PIO block transfer would have to be protected > anyway, but that's a very small part of the code.
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