From: Damien Le Moal damien.lemoal@opensource.wdc.com
[ Upstream commit 69f2c9346313ba3d3dfa4091ff99df26c67c9021 ]
Commit 2dc0b46b5ea3 ("libata: sata_down_spd_limit should return if driver has not recorded sstatus speed") changed the behavior of sata_down_spd_limit() to return doing nothing if a drive does not report a current link speed, to avoid reducing the link speed to the lowest 1.5 Gbps speed.
However, the change assumed that a speed was recorded before probing (e.g. before a suspend/resume) and set in link->sata_spd. This causes problems with adapters/drives combination failing to establish a link speed during probe autonegotiation. One example reported of this problem is an mvebu adapter with a 3Gbps port-multiplier box: autonegotiation fails, leaving no recorded link speed and no reported current link speed. Probe retries also fail as no action is taken by sata_set_spd() after each retry.
Fix this by returning early in sata_down_spd_limit() only if we do have a recorded link speed, that is, if link->sata_spd is not 0. With this fix, a failed probe not leading to a recorded link speed is retried at the lower 1.5 Gbps speed, with the link speed potentially increased later on the second revalidate of the device if the device reports that it supports higher link speeds.
Reported-by: Marius Dinu marius@psihoexpert.ro Fixes: 2dc0b46b5ea3 ("libata: sata_down_spd_limit should return if driver has not recorded sstatus speed") Reviewed-by: Niklas Cassel niklas.cassel@wdc.com Tested-by: Marius Dinu marius@psihoexpert.ro Signed-off-by: Damien Le Moal damien.lemoal@opensource.wdc.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/ata/libata-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index d13474c6d181..14150767be44 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -3051,7 +3051,7 @@ int sata_down_spd_limit(struct ata_link *link, u32 spd_limit) */ if (spd > 1) mask &= (1 << (spd - 1)) - 1; - else + else if (link->sata_spd) return -EINVAL;
/* were we already at the bottom? */