sata_down_spd_limit — adjust SATA spd limit downward
| int sata_down_spd_limit ( | struct ata_link * link, | 
| u32 spd_limit ); | 
   Adjust SATA spd limit of link downward.  Note that this
   function only adjusts the limit.  The change must be applied
   using sata_set_spd.
   
   If spd_limit is non-zero, the speed is limited to equal to or
   lower than spd_limit if such speed is supported.  If
   spd_limit is slower than any supported speed, only the lowest
   supported speed is allowed.