Merge branch 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev

* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev:
  pata_bf54x: decrease count first.
  sata_mv: re-enable hotplug, update TODO list
  sata_mv: leave SError bits untouched in mv_err_intr
  sata_mv: more interrupt handling rework
  sata_mv: tidy host controller interrupt handling
  sata_mv: simplify request/response queue handling
  sata_mv: simplify freeze/thaw bit-shift calculations
  sata_mv mask all interrupt coalescing bits
  sata_mv more cosmetics
  ata_piix: add Asus Eee 701 controller to short cable list
  libata-eh set tf flags in NCQ EH result_tf
  make sata_set_spd_needed() static
  make sata_print_link_status() static
  libata-acpi.c: remove unneeded #if's
  sata_nv: make hardreset return -EAGAIN on success
  ahci: retry enabling AHCI a few times before spitting out WARN_ON()
  libata: make WARN_ON conditions in ata_sff_hsm_move() more strict
  ATA/IDE: fix platform driver hotplug/coldplug
  sata_sis: SCR accessors return -EINVAL when requested SCR isn't available
  libata: functions with definition should not be extern

1 files changed, 13 insertions, 2 deletions

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 986e3324e302..7c4f886f1f16 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -556,16 +556,27 @@ static inline void __iomem *ahci_port_base(struct ata_port *ap)
 
 static void ahci_enable_ahci(void __iomem *mmio)
 {
+        int i;
         u32 tmp;
 
         /* turn on AHCI_EN */
         tmp = readl(mmio + HOST_CTL);
-        if (!(tmp & HOST_AHCI_EN)) {
+        if (tmp & HOST_AHCI_EN)
+                return;
+
+        /* Some controllers need AHCI_EN to be written multiple times.
+         * Try a few times before giving up.
+         */
+        for (i = 0; i < 5; i++) {
                 tmp |= HOST_AHCI_EN;
                 writel(tmp, mmio + HOST_CTL);
                 tmp = readl(mmio + HOST_CTL);   /* flush && sanity check */
-                WARN_ON(!(tmp & HOST_AHCI_EN));
+                if (tmp & HOST_AHCI_EN)
+                        return;
+                msleep(10);
         }
+
+        WARN_ON(1);
 }
 
 /**