• Ben Collins's avatar
    ieee1394: support for slow links or slow 1394b phy ports · 647dcb5f
    Ben Collins authored
    Add support for the following types of hardware:
     + nodes that have a link speed < PHY speed
     + 1394b PHYs that are less than S800 capable
     + 1394b/1394a adapter cable between two 1394b PHYs
    Also, S1600 and S3200 are now supported if IEEE1394_SPEED_MAX is raised.
    A probing function is added to nodemgr's config ROM fetching routine
    which adjusts the allowable speed if an access problem was encountered.
    Pros and Cons of the approach:
     + minimum code footprint to support this less widely used hardware
     + nearly no overhead for unaffected hardware
     - ineffective before nodemgr began to read the ROM of affected nodes
     - ineffective if ieee1394 is loaded with disable_nodemgr=1
    The speed map CSRs which are published to the bus are not touched by the
    Signed-off-by: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
    Cc: Hakan Ardo <hakan@debian.org>
    Cc: Calculex <linux@calculex.com>
    Cc: Robert J. Kosinski <robk@cmcherald.com>
    Signed-off-by: default avatarBen Collins <bcollins@ubuntu.com>