>>>>> "Paul" == Paul Mackerras <[email protected]> writes:
Paul> Jesse Barnes writes:
>> So ultimately mmiowb() is the only thing drivers really have to
>> care about on Altix (assuming they do DMA mapping correctly), and
>> the rules for that are fairly simple. Then they can additionally
>> use read_relaxed() to optimize performance a bit (quite a bit on
>> big systems).
Paul> If I can be sure that all the drivers we care about on PPC use
Paul> mmiowb correctly, I can reduce or eliminate the barrier in
Paul> write*, which would be nice.
Paul> Which drivers have been audited to make sure they use mmiowb
Paul> correctly? In particular, has the USB driver been audited?
I think the primary drivers we've looked at are drivers/net/tg3.c,
drivers/net/s2io.c, drivers/scsi/qla1280.c, and possibly the
qla[234]xxx series - thats probably it!
While we have USB on the systems, I don't think anyone has spend a lot
of time verifying it in this context. At least the keyboard and mouse
I have on this box seems to behave.
Cheers,
Jes
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