1 files changed, 15 insertions, 1 deletions

diff --git a/drivers/ata/ahci_sunxi.c b/drivers/ata/ahci_sunxi.c
index e44d675a30ec..b5aedca5ea3c 100644
--- a/drivers/ata/ahci_sunxi.c
+++ b/drivers/ata/ahci_sunxi.c
@@ -27,6 +27,12 @@
 #include <linux/regulator/consumer.h>
 #include "ahci.h"
 
+/* Insmod parameters */
+static bool enable_pmp;
+module_param(enable_pmp, bool, 0);
+MODULE_PARM_DESC(enable_pmp,
+        "Enable support for sata port multipliers, only use if you use a pmp!");
+
 #define AHCI_BISTAFR    0x00a0
 #define AHCI_BISTCR     0x00a4
 #define AHCI_BISTFCTR   0x00a8
@@ -184,7 +190,15 @@ static int ahci_sunxi_probe(struct platform_device *pdev)
                 goto disable_resources;
 
         hpriv->flags = AHCI_HFLAG_32BIT_ONLY | AHCI_HFLAG_NO_MSI |
-                       AHCI_HFLAG_NO_PMP | AHCI_HFLAG_YES_NCQ;
+                       AHCI_HFLAG_YES_NCQ;
+
+        /*
+         * The sunxi sata controller seems to be unable to successfully do a
+         * soft reset if no pmp is attached, so disable pmp use unless
+         * requested, otherwise directly attached disks do not work.
+         */
+        if (!enable_pmp)
+                hpriv->flags |= AHCI_HFLAG_NO_PMP;
 
         rc = ahci_platform_init_host(pdev, hpriv, &ahci_sunxi_port_info);
         if (rc)