On Wed, 6 Aug 2003, Oliver Neukum wrote:
> Am Mittwoch, 6. August 2003 08:30 schrieb Petko Manolov:
> > On Wed, 6 Aug 2003, Oliver Neukum wrote:
> >
> > > DMA to a part of a structure is forbidden on the noncoherent architectures.
> >
> > Didn't quite get this. What "noncoherent" is supposed to mean here? In
> > general the memory allocated for a structure which is part of the
> > kernel (or kernel module) should be as good as the one allocated by
> > kmalloc() with the given flag. Am i missing something here?
>
> Yes, coherency with respect to DMA. Sharing cachelines between data
> and buffers may lead to corruption of the transfered data on some
> architectures.
Yep, i agree. With no cache snooping on the bus one should be very
careful when transferring data to/from external devices. Thanks for
spotting it.
Petko
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