Andrey Savochkin wrote:
> On Fri, May 19, 2000 at 05:31:37PM -0400, Jeff Garzik wrote:
> > In any case, if you were thinking about it, I wouldn't blindly replace
> > writew() with udelay() or anything like that -- leave the writew() in
> > there, and add an additional udelay() if the circumstances call for it.
> > Excluding the writew() increases the potential for seeming EEPROM code
> > flakiness, because few drivers have thus far been completely audited,
> > updated, and tested for correct MMIO flush semantics.
> I do not do it blindly! :-)
> I've checked different available drivers, and all of them uses udelay()
> without any readw(), except only one which uses inw() and is proven to have
> problems. And some of these drivers have been working for years.
> So, I feel quite confidential in removing readw() altogether and implementing
> eeprom_delay via just udelay(1).
Experience seems to show that PIO reads and writes are posted on x86,
while MMIO writes might be combined before posting. So, since 95% of
the net drivers using PIO still, judging an MMIO driver from the actions
of PIO drivers may not lead to correct conclusions.
Unless there is a reason -not- to have it there, AFAICS the inw() -must-
be present.
Jeff
-- Jeff Garzik | Liberty is always dangerous, but Building 1024 | it is the safest thing we have. MandrakeSoft, Inc. | -- Harry Emerson Fosdick- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
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