libata: disable forced PORTS_IMPL for >= AHCI 1.3

commit 566d1827 upstream.

Some early controllers incorrectly reported zero ports in PORTS_IMPL
register and the ahci driver fabricates PORTS_IMPL from the number of
ports in those cases.  This hasn't mattered but with the new nvme
controllers there are cases where zero PORTS_IMPL is valid and should
be honored.

Disable the workaround for >= AHCI 1.3.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/g/CALCETrU7yMvXEDhjAUShoHEhDwifJGapdw--BKxsP0jmjKGmRw@mail.gmail.com
Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
[wt: file is drivers/ata/ahci.c in 2.6.32]
Signed-off-by: Willy Tarreau <w@1wt.eu>

drivers/ata/ahci.c

@@ -924,8 +924,8 @@ static void ahci_save_initial_config(struct pci_dev *pdev,
 		}
 	}
 
-	/* fabricate port_map from cap.nr_ports */
-	if (!port_map) {
+	/* fabricate port_map from cap.nr_ports for < AHCI 1.3 */
+	if (!port_map && vers < 0x10300) {
 		port_map = (1 << ahci_nr_ports(cap)) - 1;
 		dev_printk(KERN_WARNING, &pdev->dev,
 			   "forcing PORTS_IMPL to 0x%x\n", port_map);