diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index e793716..bf8d3b8 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -6317,7 +6317,8 @@
 		/* 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;