1 files changed, 16 insertions, 6 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 3a1ec4e715ed..164c7d9514f9 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2751,17 +2751,27 @@ int sata_down_spd_limit(struct ata_link *link)
 
 static int __sata_set_spd_needed(struct ata_link *link, u32 *scontrol)
 {
-        u32 spd, limit;
+        struct ata_link *host_link = &link->ap->link;
+        u32 limit, target, spd;
 
-        if (link->sata_spd_limit == UINT_MAX)
-                limit = 0;
+        limit = link->sata_spd_limit;
+
+        /* Don't configure downstream link faster than upstream link.
+         * It doesn't speed up anything and some PMPs choke on such
+         * configuration.
+         */
+        if (!ata_is_host_link(link) && host_link->sata_spd)
+                limit &= (1 << host_link->sata_spd) - 1;
+
+        if (limit == UINT_MAX)
+                target = 0;
         else
-                limit = fls(link->sata_spd_limit);
+                target = fls(limit);
 
         spd = (*scontrol >> 4) & 0xf;
-        *scontrol = (*scontrol & ~0xf0) | ((limit & 0xf) << 4);
+        *scontrol = (*scontrol & ~0xf0) | ((target & 0xf) << 4);
 
-        return spd != limit;
+        return spd != target;
 }
 
 /**