1 files changed, 36 insertions, 0 deletions

diff --git a/drivers/ata/ata_piix.c b/drivers/ata/ata_piix.c
index 22752e46b34f..0ff96a06374e 100644
--- a/drivers/ata/ata_piix.c
+++ b/drivers/ata/ata_piix.c
@@ -1173,6 +1173,39 @@ static void __devinit piix_init_sata_map(struct pci_dev *pdev,
         hpriv->map = map;
 }
 
+static void piix_iocfg_bit18_quirk(struct pci_dev *pdev)
+{
+        static struct dmi_system_id sysids[] = {
+                {
+                        /* Clevo M570U sets IOCFG bit 18 if the cdrom
+                         * isn't used to boot the system which
+                         * disables the channel.
+                         */
+                        .ident = "M570U",
+                        .matches = {
+                                DMI_MATCH(DMI_SYS_VENDOR, "Clevo Co."),
+                                DMI_MATCH(DMI_PRODUCT_NAME, "M570U"),
+                        },
+                },
+        };
+        u32 iocfg;
+
+        if (!dmi_check_system(sysids))
+                return;
+
+        /* The datasheet says that bit 18 is NOOP but certain systems
+         * seem to use it to disable a channel.  Clear the bit on the
+         * affected systems.
+         */
+        pci_read_config_dword(pdev, PIIX_IOCFG, &iocfg);
+        if (iocfg & (1 << 18)) {
+                dev_printk(KERN_INFO, &pdev->dev,
+                           "applying IOCFG bit18 quirk\n");
+                iocfg &= ~(1 << 18);
+                pci_write_config_dword(pdev, PIIX_IOCFG, iocfg);
+        }
+}
+
 /**
  *      piix_init_one - Register PIIX ATA PCI device with kernel services
  *      @pdev: PCI device to register
@@ -1234,6 +1267,9 @@ static int piix_init_one (struct pci_dev *pdev, const struct pci_device_id *ent)
                               piix_map_db_table[ent->driver_data]);
         }
 
+        /* apply IOCFG bit18 quirk */
+        piix_iocfg_bit18_quirk(pdev);
+
         /* On ICH5, some BIOSen disable the interrupt using the
          * PCI_COMMAND_INTX_DISABLE bit added in PCI 2.3.
          * On ICH6, this bit has the same effect, but only when