diff options
Diffstat (limited to 'drivers/ata/libata-core.c')
| -rw-r--r-- | drivers/ata/libata-core.c | 29 |
1 files changed, 22 insertions, 7 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index 5718c247e23..c325b7a4246 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -2389,21 +2389,35 @@ int sata_down_spd_limit(struct ata_port *ap) u32 sstatus, spd, mask; int rc, highbit; + if (!sata_scr_valid(ap)) + return -EOPNOTSUPP; + + /* If SCR can be read, use it to determine the current SPD. + * If not, use cached value in ap->sata_spd. + */ rc = sata_scr_read(ap, SCR_STATUS, &sstatus); - if (rc) - return rc; + if (rc == 0) + spd = (sstatus >> 4) & 0xf; + else + spd = ap->sata_spd; mask = ap->sata_spd_limit; if (mask <= 1) return -EINVAL; + + /* unconditionally mask off the highest bit */ highbit = fls(mask) - 1; mask &= ~(1 << highbit); - spd = (sstatus >> 4) & 0xf; - if (spd <= 1) - return -EINVAL; - spd--; - mask &= (1 << spd) - 1; + /* Mask off all speeds higher than or equal to the current + * one. Force 1.5Gbps if current SPD is not available. + */ + if (spd > 1) + mask &= (1 << (spd - 1)) - 1; + else + mask &= 1; + + /* were we already at the bottom? */ if (!mask) return -EINVAL; @@ -5995,6 +6009,7 @@ void ata_dev_init(struct ata_device *dev) /* SATA spd limit is bound to the first device */ ap->sata_spd_limit = ap->hw_sata_spd_limit; + ap->sata_spd = 0; /* High bits of dev->flags are used to record warm plug * requests which occur asynchronously. Synchronize using |