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    USB: remove uses of URB_NO_SETUP_DMA_MAP · 0ede76fc
    Alan Stern 提交于
    This patch (as1350) removes all usages of coherent buffers for USB
    control-request setup-packet buffers.  There's no good reason to
    reserve coherent memory for these things; control requests are hardly
    ever used in large quantity (the major exception is firmware
    transfers, and they aren't time-critical).  Furthermore, only seven
    drivers used it.  We might as well always use streaming DMA mappings
    for setup-packet buffers, and remove some extra complexity from
    usbcore.
    
    The DMA-mapping portion of hcd.c is currently in flux.  A separate
    patch will be submitted to remove support for URB_NO_SETUP_DMA_MAP
    after everything else settles down.  The removal should go smoothly,
    as by then nobody will be using it.
    Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
    Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
    0ede76fc
urb.c 27.5 KB