Re: 2.6.24-git: kmap_atomic() WARN_ON()

Alan Cox
2008-02-27T00:15:33Z

> 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