Messages in this thread | | | Date | Wed, 27 Feb 2008 00:02:22 +0000 | From | Alan Cox <> | Subject | Re: 2.6.24-git: kmap_atomic() WARN_ON() |
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> Aside: The "FIXME: use bounce buffer" comment above indicates the more > optimal PIO data xfer approach of > > local_irq_save() > kmap_atomic() > memcpy into bounce buffer > kunmap_atomic() > local_irq_restore() > > /* do slow PIO bitbanging data transfer */ > ap->ops->data_xfer(...)
Definitely - older PATA controllers are unbuffered. A PIO_0 transfer is running at ISA speed with IRQs off. Guaranteed to give Ingo's RT a blip.
Alan
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