libata: disable forced PORTS_IMPL for >= AHCI 1.3

commit 566d1827df2ef0cbe921d3d6946ac3007b1a6938 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index b18f569f74c7229e378acf8d0244702904148e46..d04f5c8dbbdc479a4f16ffa11800fc12c97e2c3e 100644 (file)
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -486,8 +486,8 @@ void ahci_save_initial_config(struct device *dev,
                }
        }
 
-       /* 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_warn(dev, "forcing PORTS_IMPL to 0x%x\n", port_map);