• David Milburn's avatar
    libata: sata_down_spd_limit should return if driver has not recorded sstatus speed · 2dc0b46b
    David Milburn authored
    During hotplug, it is possible for 6Gbps link speed to be limited all
    the way down to 1.5 Gbps which may lead to a slower link speed when
    drive is re-connected.
    
    This behavior has been seen on a Intel Lewisburg SATA controller
    (8086:a1d2) with HGST HUH728080ALE600 drive where SATA link speed was
    limited to 1.5 Gbps and when re-connected the link came up 3.0 Gbps.
    
    This patch was retested on above configuration and showed the
    hotplugged link to come back online at max speed (6Gbps). I did not
    see the downgrade when testing on Intel C600/X79, but retested patched
    linux-4.14-rc5 kernel and didn't see any side effects from this
    change. Also, successfully retested hotplug on port multiplier 3Gbps
    link.
    
    tj: Minor comment updates.
    Signed-off-by: default avatarDavid Milburn <dmilburn@redhat.com>
    Signed-off-by: default avatarTejun Heo <tj@kernel.org>
    2dc0b46b
libata-core.c 188 KB