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    SubjectRe: DAC960 in 2.5.38, with new changes

    Ok, thanks for explaining!

    At some point, I want to step back and look over the BIO and DMA code.
    Possibly this will be my "project" for October :-)

    On Tue, Sep 24, 2002 at 11:21:45AM -0700, David Mosberger wrote:
    > >>>>> On Tue, 24 Sep 2002 10:28:43 -0700, Dave Olien <dmo@osdl.org> said:
    >
    > Dave> Hmm, interesting. A big part of what I'm doing to the driver
    > Dave> right now is plugging in calls to the PCI DMA interfaces.
    >
    > That's fine (actually, it's more than that: it's great!).
    >
    > Dave> So unless the underlying implementation is aware of these
    > Dave> platform limitations and "doing the right thing", I'm adding
    > Dave> a bunch of bounce buffer activity for many ia64 platforms.
    > Dave> That would be too bad.
    >
    > The idea is to do something along these lines:
    >
    > o Use PCA DMA interface for managing all DMA buffers.
    >
    > o If sizeof(dma_addr_t) > 4, turn on DAC mode and call
    > pci_set_dma_mask(dev, MAX_ADDR), where MAX_ADDR is the maximum
    > address that can be reached by the controller (i.e.,
    > 0xffffffffffffffff for a truly 64-bit-capable PCI controller).
    >
    > This way, everything should work out correctly and with good
    > performance on all imaginable platforms (ia64 with and without
    > hardware I/O TLB, plain x86, x86 with >4GB RAM, SPARC64 with 32-bit
    > dma_addr_t, etc.).
    >
    > --david
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