In message <20031217093933.B16120@xxxxxxxxxxxxxxxxxxxxxx>
Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx> wrote:
> If anyone wants to guarantee uncached accesses while mmaping /dev/mem,
> they must open /dev/mem with the O_SYNC flag. I would suggest teaching
> XFree to use this flag as appropriate, so that it always explicitly
> tells the kernel the behaviour it expects.
I'll note this to the XFree86 people; thanks for confirming this.
> That said, the kernel traditionally only mmaps mappings above the RAM
> as uncached by default, and at or below the RAM as cached. I suspect
> your platform probably has the memory mapped at an address higher than
> the devices.
Yes, that's certainly the case.
--
Peter Naulls - peter@xxxxxxxxxx | http://www.chocky.org/
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