• Roland Dreier's avatar
    IB/mlx4: Handle new FW requirement for send request prefetching · 0e6e7416
    Roland Dreier authored
    New ConnectX firmware introduces FW command interface revision 2,
    which requires that for each QP, a chunk of send queue entries (the
    "headroom") is kept marked as invalid, so that the HCA doesn't get
    confused if it prefetches entries that haven't been posted yet.  Add
    code to the driver to do this, and also update the user ABI so that
    userspace can request that the prefetcher be turned off for userspace
    QPs (we just leave the prefetcher on for all kernel QPs).
    
    Unfortunately, marking send queue entries this way is confuses older
    firmware, so we change the driver to allow only FW command interface
    revisions 2.  This means that users will have to update their firmware
    to work with the new driver, but the firmware is changing quickly and
    the old firmware has lots of other bugs anyway, so this shouldn't be too
    big a deal.
    
    Based on a patch from Jack Morgenstein <jackm@dev.mellanox.co.il>.
    Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
    0e6e7416
qp.c 38.3 KB