Re: [PATCH 28 of 39] IB/ipath - Fixes a bug where our delay for EEPROM no longer works due to compiler reordering

From: Roland Dreier
Date: Fri Jun 30 2006 - 17:06:46 EST


> > static void i2c_wait_for_writes(struct ipath_devdata *dd)
> > {
> > + mb();
> > (void)ipath_read_kreg32(dd, dd->ipath_kregs->kr_scratch);
> > }

> That's a bit weird. I wouldn't have expected the compiler to muck around
> with a readl().

I never liked this patch. The last time it came up there were
conflicting answers about whether it was a code generation bug or a
real issue talking to hardware or what. At the least I think this
merits a big comment explain what's going on -- and even better would
be really understanding the bug that's being fixed so that we're
confident it is indeed a real fix.

- R.
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