• Arthur Kepner's avatar
    IB/mthca: Use mmiowb after doorbell ring · 1f5c23e2
    Arthur Kepner authored
    We discovered a problem when running IPoIB applications on multiple
    CPUs on an Altix system. Many messages such as:
    
    ib_mthca 0002:01:00.0: SQ 000014 full (19941644 head, 19941707 tail, 64 max, 0 nreq)
    
    appear in syslog, and the driver wedges up.
    
    Apparently this is because writes to the doorbells from different CPUs
    reach the device out of order. The following patch adds mmiowb() calls
    after doorbell rings to ensure the doorbell writes are ordered.
    Signed-off-by: default avatarArthur Kepner <akepner@sgi.com>
    Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
    1f5c23e2
mthca_cq.c 25.8 KB