libata: fix hw_sata_spd_limit initialization

hw_sata_spd_limit used to be incorrectly initialized to zero instead
of UINT_MAX if SPD is zero in SControl register.  This breaks PHY
speed down.  Fix it.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index e7937166a8b..bf8d3b8c171 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -6317,7 +6317,8 @@ int ata_host_register(struct ata_host *host, struct scsi_host_template *sht)
                 /* init sata_spd_limit to the current value */
                 if (sata_scr_read(ap, SCR_CONTROL, &scontrol) == 0) {
                         int spd = (scontrol >> 4) & 0xf;
-                        ap->hw_sata_spd_limit &= (1 << spd) - 1;
+                        if (spd)
+                                ap->hw_sata_spd_limit &= (1 << spd) - 1;
                 }
                 ap->sata_spd_limit = ap->hw_sata_spd_limit;