Re: [PATCH v2] libata: disable forced PORTS_IMPL for >= AHCI 1.3

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
---
Hello, Andy.

Can you please see whether this one works?

Thanks.

  drivers/ata/libahci.c |    5 +++--
  1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index d61740e..a91432a 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c

@@ -496,8 +496,9 @@ void ahci_save_initial_config(struct device *dev, struct ahci_host_priv *hpriv)
  		}
  	}

-	/* 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 >> 16) ||
+			  ((vers >> 16) == 1 && (vers & 0xFFFF) < 0x300))) {