[PATCH] ata_piix: implement force_pcs module parameter

This patch implements force_pcs module parameter for ata_piix.  If 1,
PCS is ignored, 2 honored.  As there seem to be quite a few ICHs w/
impaired PCS, this option will be useful for cases where the default
setting doesn't work.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/scsi/ata_piix.c b/drivers/scsi/ata_piix.c
index 3b98f18..2d20caf 100644 (file)
--- a/drivers/scsi/ata_piix.c
+++ b/drivers/scsi/ata_piix.c
@@ -468,6 +468,11 @@ MODULE_LICENSE("GPL");
 MODULE_DEVICE_TABLE(pci, piix_pci_tbl);
 MODULE_VERSION(DRV_VERSION);
 
+static int force_pcs = 0;
+module_param(force_pcs, int, 0444);
+MODULE_PARM_DESC(force_pcs, "force honoring or ignoring PCS to work around "
+                "device mis-detection (0=default, 1=ignore PCS, 2=honor PCS)");
+
 /**
  *     piix_pata_cbl_detect - Probe host controller cable detect info
  *     @ap: Port for which cable detect info is desired
@@ -812,6 +817,7 @@ static int __devinit piix_check_450nx_errata(struct pci_dev *ata_dev)
 }
 
 static void __devinit piix_init_pcs(struct pci_dev *pdev,
+                                   struct ata_port_info *pinfo,
                                    const struct piix_map_db *map_db)
 {
        u16 pcs, new_pcs;
@@ -825,6 +831,18 @@ static void __devinit piix_init_pcs(struct pci_dev *pdev,
                pci_write_config_word(pdev, ICH5_PCS, new_pcs);
                msleep(150);
        }
+
+       if (force_pcs == 1) {
+               dev_printk(KERN_INFO, &pdev->dev,
+                          "force ignoring PCS (0x%x)\n", new_pcs);
+               pinfo[0].host_flags |= PIIX_FLAG_IGNORE_PCS;
+               pinfo[1].host_flags |= PIIX_FLAG_IGNORE_PCS;
+       } else if (force_pcs == 2) {
+               dev_printk(KERN_INFO, &pdev->dev,
+                          "force honoring PCS (0x%x)\n", new_pcs);
+               pinfo[0].host_flags &= ~PIIX_FLAG_IGNORE_PCS;
+               pinfo[1].host_flags &= ~PIIX_FLAG_IGNORE_PCS;
+       }
 }
 
 static void __devinit piix_init_sata_map(struct pci_dev *pdev,
@@ -933,7 +951,8 @@ static int piix_init_one (struct pci_dev *pdev, const struct pci_device_id *ent)
        if (host_flags & ATA_FLAG_SATA) {
                piix_init_sata_map(pdev, port_info,
                                   piix_map_db_table[ent->driver_data]);
-               piix_init_pcs(pdev, piix_map_db_table[ent->driver_data]);
+               piix_init_pcs(pdev, port_info,
+                             piix_map_db_table[ent->driver_data]);
        }
 
        /* On ICH5, some BIOSen disable the interrupt using the