Messages in this thread | | | From | Nick Warne <> | Subject | Re: hda: irq timeout: status=0xd0 DMA question | Date | Sun, 26 Feb 2006 17:01:53 +0000 |
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On Sunday 26 February 2006 14:15, Jesper Juhl wrote: > On 2/26/06, Mark Lord <lkml@rtr.ca> wrote: > > Nick Warne wrote:
> > > I dunno what happened to the drive that time (this is the only logs of > > > the incident) and I turned DMA back on with hdparm - but my question is > > > why is DMA turned off and then left off after a reset? > > > > When I wrote that code in the mid-1990s, the number one causes of drives > > getting confused (and needing to be reset again), were improper DMA > > timings, cablings, and buggy DMA firmware. > > > > So at the time, since DMA was a newish feature for IDE, we figured that > > turning it off after reset was a Good Thing(tm). > > > > And it was. A more modern implementation might try being more clever > > about such stuff, and Tejun is working on something like that for libata.
OK, I see...
> > In the meanwhile, you could have a shell script just loop in the > > background, turning DMA back on periodically. If you care.
I don't like - anyway, it's the first time I have ever seen this on that box in 4 years, it was a quirk somewhere I think (maybe a power fluctuation or the like).
> Or how about an option for the IDE driver to "not do that" that people > could enable if needed/wanted? > Or just change the code to "not do that" since we are no longer in the > mid-1990s?
Good idea!
Nick -- "Person who say it cannot be done should not interrupt person doing it." -Chinese Proverb - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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