• Edward Cree's avatar
    sfc: allow PIO more often · de1deff9
    Edward Cree authored
    If an option descriptor has been sent on a queue but not followed by a
     packet, there will have been no completion event, so the read and write
     counts won't match and we'll think we can't do PIO.  This combines with
     the fact that we have two TX queues (for en/disable checksum offload),
     and that both must be empty for PIO to happen.
    This patch adds a separate "packet_write_count" that tracks the most
     recent write_count we expect to see a completion event for; this excludes
     option descriptors but _includes_ PIO descriptors (even though they look
     like option descriptors).  This is then used, rather than write_count,
     in efx_nic_tx_is_empty().
    We only bother to maintain packet_write_count on EF10, since on Siena
     (a) there are no option descriptors and it always equals write_count, and
     (b) there's no PIO, so we don't need it anyway.
    Signed-off-by: default avatarEdward Cree <ecree@solarflare.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    de1deff9
tx.c 24.3 KB