Messages in this thread | | | Date | Fri, 1 Sep 2006 11:23:12 -0700 | From | Andrew Morton <> | Subject | Re: 2.6.18-rc5-mm1: drivers/infiniband/hw/amso1100/c2.c compile error |
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On Fri, 01 Sep 2006 10:34:24 -0700 Roland Dreier <rdreier@cisco.com> wrote:
> Andrew> What's __raw_writeq() supposed to do, anyway? On alpha > Andrew> it's writeq() without an mb(). On parisc it's writeq() > Andrew> only the data is byte-reversed. On sparc64() it's > Andrew> incomprehensible. On everything else it's writeq(). > > My understanding is that __raw_writeq() is like writeq() except not > strongly ordered and without the byte-swap on big-endian > architectures. The __raw_writeX() variants are convenient to avoid > having to write inefficient code like writel(swab32(foo), ...) when > talking to a PCI device that wants big-endian data. Without the raw > variant, you end up with a double swap on big-endian architectures. > > sparc64 looks wrong, since __raw_writeq() seems identical to writeq(), > which seems to imply it's going to swab what is stores. >
OK. Can we please stop hacking around this in drivers and
a) work out what it's supposed to do
b) document that (Documentation/DocBook/deviceiobook.tmpl or code comment or whatever)
c) tell arch maintainers? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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