Patch "libata: disable forced PORTS_IMPL for >= AHCI 1.3" has been added to the 4.4-stable tree

Patch "libata: disable forced PORTS_IMPL for >= AHCI 1.3" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    libata: disable forced PORTS_IMPL for >= AHCI 1.3

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     libata-disable-forced-ports_impl-for-ahci-1.3.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 566d1827df2ef0cbe921d3d6946ac3007b1a6938 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Fri, 15 Jan 2016 15:13:05 -0500
Subject: libata: disable forced PORTS_IMPL for >= AHCI 1.3

From: Tejun Heo <tj@kernel.org>

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>

---
 drivers/ata/libahci.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -495,8 +495,8 @@ void ahci_save_initial_config(struct 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);
 


Patches currently in stable-queue which might be from tj@kernel.org are

queue-4.4/ahci-intel-dnv-device-ids-sata.patch
queue-4.4/printk-do-cond_resched-between-lines-while-outputting-to-consoles.patch
queue-4.4/libata-disable-forced-ports_impl-for-ahci-1.3.patch