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    [SCSI] libsas: Add SATA support to STP piece for SATA on SAS expanders · 1acce194
    James Bottomley authored
    
    
    This patch adds support for SATA over SAS expanders to the previous two
    SATA support in libsas patches.
    
    There were a couple of nasty non trivial things to sort out before this
    one could be made to work.
    
    Firstly, I'd like to thank Doug Gilbert for diagnosing a problem with
    the LSI expanders where the REPORT_SATA_PHY command was returning the
    D2H FIS in the wrong order (Although, here, I think I have to blame the
    SAS standards which specifies the FIS "shall be returned in little
    endian format" and later on "which means resp[24] shall be FIS type"
    The latter, of course, implying big endian format).  Just to make sure,
    I put a check for the D2H FIS type being in the wrong position and
    reverse the FIS data if it is.
    
    The second is a problem outlined in Annex G of the SAS standard (again,
    a technical point with D2H FIS ... necessitating a phy reset on certain
    conditions).
    
    With the patch, I can now see my SATA-1 disk in a cascaded expander
    configuration.
    
    Signed-off-by: default avatarJames Bottomley <James.Bottomley@SteelEye.com>
    1acce194