Messages in this thread | | | Subject | Re: Strange IO behaviour on wakeup from sleep | From | Benjamin Herrenschmidt <> | Date | Thu, 28 Oct 2004 08:40:31 +1000 |
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On Wed, 2004-10-27 at 07:18 -0700, Zachary Amsden wrote:
> I would tend to be very suspicious of DMA not being restored correctly > because on some systems, prior to or during suspend, DMA may be shutdown > to conserve power. There are changes afloat that touch suspend/resume, > and there have been historical problems with DMA not being restored > properly after wakeup on some laptops.
DMA is restored, and the resulting is way slower than what PIO would explain anyway. I get less than 100Kb/sec !
(I wrote the IDE suspend/resume code and the driver for this chipset, so I'm fairly sure that side is ok, it didn't change for a while, but I'll double check in case Bart latest updates broke something).
> Although this may be another shot in the dark, it might rule out the DMA > problem: try cat /proc/ide/yourchipset before and after suspend and > note any changes. Failing that, use hdparm to turn off DMA before > suspend and see if the performance suffers to the same degree as after > wakeup.
Tried all of that.
Ben.
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