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    Subject[PATCH v6] Align tegra-ehci DMA transfers to 32B
    Date
    This small set of patches fixes an issue where DMA from the tegra EHCI
    controller could be corrupted. It was most commonly seen with USB network
    adapters, though in theory it could happen with any USB traffic.

    Note: An attempt was made to fix this specifically for network devices with
    commit 367c3aab, which set NET_IP_ALIGN to 0 and NET_SKB_PAD to 32.
    Unfortunately, not all network drivers honor them (presumably since these are
    intended as optimizations rather than hard rules). This does mean that
    properly behaved network drivers should fall through this code with very little
    overhead, however.

    Version 2 of this patchset gets rid of the HCD placeholder in the flags and
    instead simply reserves the flag globally for this use.

    Version 3 makes the hook definition and commit message much more verbose, and
    moves the new flag from the second patch to the first.

    Version 4 adds logic to prevent data copy-out on failure.

    Version 5 rebases against linux-tegra-2.6.37.

    Version 6 renames the map/unmap exported functions from the hcd core to have
    usb_hcd prefixes as an additional patch. It also fixes some comment
    formatting, and removes the logic added in version 4 to skip the memcpy from
    the temp buffer on failure (some data may still be good).



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