[PATCH] ipr: PCI-X capabilities setup fix

From: Andrew Vasquez <andrew.vasquez@qlogic.com>

While performing some PCI-X command register tuning with some of
QLogic's cards, I stumbled upon some suspect code in ipr.c.  It appears
the two functions ipr_save_pcix_cmd_reg() and ipr_set_pcix_cmd_reg() are
actually reading/updating the PCI-X capabilities register and not in
fact the PCI-X command register -- some code from
ipr_save_pcix_cmd_reg():

	...
        int pcix_cmd_reg = pci_find_capability(ioa_cfg->pdev, PCI_CAP_ID_PCIX);

        if (pcix_cmd_reg == 0) {
                dev_err(&ioa_cfg->pdev->dev, "Failed to save PCI-X command register\n");
                return -EIO;
        }

pcix_cmd_reg points to the PCI-X capabilities register.  Yet, the read:

        if (pci_read_config_word(ioa_cfg->pdev, pcix_cmd_reg,
                                 &ioa_cfg->saved_pcix_cmd_reg) != PCIBIOS_SUCCESSFUL) {
                dev_err(&ioa_cfg->pdev->dev, "Failed to save PCI-X command register\n");
                return -EIO;
        }

and subsequent update of the bits:

        ioa_cfg->saved_pcix_cmd_reg |= PCI_X_CMD_DPERR_E | PCI_X_CMD_ERO;

should actually apply to the PCI-X Command register 2 bytes further into
config space.  So, the following:

        if (pci_read_config_word(ioa_cfg->pdev, pcix_cmd_reg,

should actually read as:

        if (pci_read_config_word(ioa_cfg->pdev, pcix_cmd_reg + PCI_X_CMD,

The same is true for the 'save' case.

Luckily, most devices hardwire the PCI-X capabilities register so the
write is effectively a NOOP.
Signed-off-by: Brian King <brking@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/ipr.c

@@ -542,7 +542,7 @@ static int ipr_save_pcix_cmd_reg(struct ipr_ioa_cfg *ioa_cfg)
 		return -EIO;
 	}
 
-	if (pci_read_config_word(ioa_cfg->pdev, pcix_cmd_reg,
+	if (pci_read_config_word(ioa_cfg->pdev, pcix_cmd_reg + PCI_X_CMD,
 				 &ioa_cfg->saved_pcix_cmd_reg) != PCIBIOS_SUCCESSFUL) {
 		dev_err(&ioa_cfg->pdev->dev, "Failed to save PCI-X command register\n");
 		return -EIO;
@@ -564,7 +564,7 @@ static int ipr_set_pcix_cmd_reg(struct ipr_ioa_cfg *ioa_cfg)
 	int pcix_cmd_reg = pci_find_capability(ioa_cfg->pdev, PCI_CAP_ID_PCIX);
 
 	if (pcix_cmd_reg) {
-		if (pci_write_config_word(ioa_cfg->pdev, pcix_cmd_reg,
+		if (pci_write_config_word(ioa_cfg->pdev, pcix_cmd_reg + PCI_X_CMD,
 					  ioa_cfg->saved_pcix_cmd_reg) != PCIBIOS_SUCCESSFUL) {
 			dev_err(&ioa_cfg->pdev->dev, "Failed to setup PCI-X command register\n");
 			return -EIO;