[3.16.y-ckt stable] Patch "ahci: disable MSI instead of NCQ on Samsung pci-e SSDs on macbooks" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    ahci: disable MSI instead of NCQ on Samsung pci-e SSDs on macbooks

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt2.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From d14dfad7b2a84048e06f4d9ef61ba2281f4a6ce2 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj at kernel.org>
Date: Mon, 27 Oct 2014 10:22:56 -0400
Subject: ahci: disable MSI instead of NCQ on Samsung pci-e SSDs on macbooks

commit 66a7cbc303f4d28f201529b06061944d51ab530c upstream.

Samsung pci-e SSDs on macbooks failed miserably on NCQ commands, so
67809f85d31e ("ahci: disable NCQ on Samsung pci-e SSDs on macbooks")
disabled NCQ on them.  It turns out that NCQ is fine as long as MSI is
not used, so let's turn off MSI and leave NCQ on.

Signed-off-by: Tejun Heo <tj at kernel.org>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=60731
Tested-by: <dorin at i51.org>
Tested-by: Imre Kaloz <kaloz at openwrt.org>
Fixes: 67809f85d31e ("ahci: disable NCQ on Samsung pci-e SSDs on macbooks")
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/ata/ahci.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index f0f8ae1197e2..d5fc45ae867b 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -60,6 +60,7 @@ enum board_ids {
 	/* board IDs by feature in alphabetical order */
 	board_ahci,
 	board_ahci_ign_iferr,
+	board_ahci_nomsi,
 	board_ahci_noncq,
 	board_ahci_nosntf,
 	board_ahci_yes_fbs,
@@ -121,6 +122,13 @@ static const struct ata_port_info ahci_port_info[] = {
 		.udma_mask	= ATA_UDMA6,
 		.port_ops	= &ahci_ops,
 	},
+	[board_ahci_nomsi] = {
+		AHCI_HFLAGS	(AHCI_HFLAG_NO_MSI),
+		.flags		= AHCI_FLAG_COMMON,
+		.pio_mask	= ATA_PIO4,
+		.udma_mask	= ATA_UDMA6,
+		.port_ops	= &ahci_ops,
+	},
 	[board_ahci_noncq] = {
 		AHCI_HFLAGS	(AHCI_HFLAG_NO_NCQ),
 		.flags		= AHCI_FLAG_COMMON,
@@ -475,10 +483,10 @@ static const struct pci_device_id ahci_pci_tbl[] = {
 	{ PCI_VDEVICE(ASMEDIA, 0x0612), board_ahci },	/* ASM1062 */

 	/*
-	 * Samsung SSDs found on some macbooks.  NCQ times out.
-	 * https://bugzilla.kernel.org/show_bug.cgi?id=60731
+	 * Samsung SSDs found on some macbooks.  NCQ times out if MSI is
+	 * enabled.  https://bugzilla.kernel.org/show_bug.cgi?id=60731
 	 */
-	{ PCI_VDEVICE(SAMSUNG, 0x1600), board_ahci_noncq },
+	{ PCI_VDEVICE(SAMSUNG, 0x1600), board_ahci_nomsi },

 	/* Enmotus */
 	{ PCI_DEVICE(0x1c44, 0x8000), board_ahci },
--
2.1.0