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    SubjectRe: [PATCH 53 of 53] ipath - add memory barrier when waiting for writes
    On Mon, 2006-05-15 at 08:57 -0700, Roland Dreier wrote:
    > > static void i2c_wait_for_writes(struct ipath_devdata *dd)
    > > {
    > > + mb();
    > > (void)ipath_read_kreg32(dd, dd->ipath_kregs->kr_scratch);
    > > }
    > This needs a comment explaining why it's needed. A memory barrier
    > before a readl() looks very strange since readl() should be ordered anyway.

    Yeah. It's actually working around what appears to be a gcc bug if the
    kernel is compiled with -Os. Ralph knows the details; he can give a
    more complete answer.


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      Last update: 2006-05-15 23:13    [W:0.018 / U:1.264 seconds]
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