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    SubjectRe: dma_alloc_coherent() on PPC32: physical addresses above 2G possible?
    On Sun, 20 Jul 2008 21:25:51 +0200
    Stefan Richter <stefanr@s5r6.in-berlin.de> wrote:

    > Arjan van de Ven wrote:
    > > On Sun, 20 Jul 2008 20:36:23 +0200
    > > Stefan Richter <stefanr@s5r6.in-berlin.de> wrote:
    > >
    > >> PS: I don't want to set the DMA mask of this device to
    > >> DMA_31BIT_MASK because that would be detrimental to other functions
    > >> of the device. It's a TI TSB43AB22A FireWire controller.
    > >
    > > Hi,
    > >
    > > just want to mention that you can set the coherent mask separately
    > > from the generic mask... is that sufficient for your load?
    > > (you can even set it just for this allocation..)
    >
    > Hmm. Would that be done this way?
    > During probe:
    >
    > if (chip_is_tsb43ab22a) {
    > if (dma_supported(dev, DMA_31BIT_MASK))
    > chip->needs_dma_mask_workaround = 1;
    > else
    > chip->needs_some_other_workaround = 1;
    > }

    btw it might be nicer to make this

    chip->something_special_mask = DMA_31BIT_MASK;

    then you can just use the mask from this struct rather than another
    check


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