Messages in this thread | | | Date | Tue, 18 Apr 2006 20:44:03 -0600 | From | Robert Hancock <> | Subject | Re: [PATCH 1/1] ide: Allow disabling of UDMA for Compact Flash devices |
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James Ausmus wrote: > This is exactly the situation that I have with 2 separate "dumb" (just > physical interfaces, essentially - not at all detectable) IDE->CF > adapters - both the IDE controller and the CF media support several > UDMA modes, so the IDE driver throws the CF device into UDMA mode on > bootup. However, as the physical interface between the IDE cable and > the CF socket is poorly engineered, it cannot handle the higher > speeds, causing the timeout errors. For some people, this can just be > fixed with an ide=nodma boot option, but as I also have a (quite > large) rotating media device on the controller, this is not an option, > as, if a fsck is performed on a boot, the boot-up time is upwards of > 30 minutes.
If it's like some of the CF-IDE adapters I've seen, the DMA request/ack lines likely aren't even wired up between the card and the cable. There's no way the kernel can detect that DMA is not actually possible on such a card without trying and waiting for it to timeout. (I've seen a few which have jumpers which select whether to connect these or not - haven't a clue why you wouldn't want to hook those up unconditionally..)
Isn't there an option to disable DMA for a specific IDE channel (ide2=nodma or something like that)?
-- Robert Hancock Saskatoon, SK, Canada To email, remove "nospam" from hancockr@nospamshaw.ca Home Page: http://www.roberthancock.com/
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