linux-kernel - [70/98] ahci: disable SNotification capability for ich8

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Date:	Tue, 26 Jan 2010 15:34:36 -0800
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org
Cc:	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Shaohua Li <shaohua.li@...el.com>,
	Jeff Garzik <jgarzik@...hat.com>
Subject: [70/98] ahci: disable SNotification capability for ich8

2.6.32-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Shaohua Li <shaohua.li@...el.com>

commit 1b677afda44f7882b7e257d6f025d006ec5d14f9 upstream.

I obseved there is a sata_async_notification() for every ahci
interrupt. But the async notification does nothing (this is hard
disk drive and no pmp). This cause cpu wastes some time on sntf
register access.

It appears ICH AHCI doesn't support SNotification register, but the
controller reports it does. After quirking it, the async notification
disappears.

PS. it appears all ICH don't support SNotification register from ICH
manual, don't know if we need quirk all ICH. I don't have machines
with all kinds of ICH.

Signed-off-by: Shaohua Li <shaohua.li@...el.com>
Signed-off-by: Jeff Garzik <jgarzik@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 drivers/ata/ahci.c |   20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -113,6 +113,7 @@ enum {
 	board_ahci_mcp65	= 6,
 	board_ahci_nopmp	= 7,
 	board_ahci_yesncq	= 8,
+	board_ahci_nosntf	= 9,
 
 	/* global controller registers */
 	HOST_CAP		= 0x00, /* host capabilities */
@@ -235,6 +236,7 @@ enum {
 	AHCI_HFLAG_NO_SUSPEND		= (1 << 10), /* don't suspend */
 	AHCI_HFLAG_SRST_TOUT_IS_OFFLINE	= (1 << 11), /* treat SRST timeout as
 							link offline */
+	AHCI_HFLAG_NO_SNTF		= (1 << 12), /* no sntf */
 
 	/* ap->flags bits */
 
@@ -508,7 +510,7 @@ static const struct ata_port_info ahci_p
 		.udma_mask	= ATA_UDMA6,
 		.port_ops	= &ahci_ops,
 	},
-	/* board_ahci_yesncq */
+	[board_ahci_yesncq] =
 	{
 		AHCI_HFLAGS	(AHCI_HFLAG_YES_NCQ),
 		.flags		= AHCI_FLAG_COMMON,
@@ -516,6 +518,14 @@ static const struct ata_port_info ahci_p
 		.udma_mask	= ATA_UDMA6,
 		.port_ops	= &ahci_ops,
 	},
+	[board_ahci_nosntf] =
+	{
+		AHCI_HFLAGS	(AHCI_HFLAG_NO_SNTF),
+		.flags		= AHCI_FLAG_COMMON,
+		.pio_mask	= ATA_PIO4,
+		.udma_mask	= ATA_UDMA6,
+		.port_ops	= &ahci_ops,
+	},
 };
 
 static const struct pci_device_id ahci_pci_tbl[] = {
@@ -531,7 +541,7 @@ static const struct pci_device_id ahci_p
 	{ PCI_VDEVICE(INTEL, 0x2683), board_ahci }, /* ESB2 */
 	{ PCI_VDEVICE(INTEL, 0x27c6), board_ahci }, /* ICH7-M DH */
 	{ PCI_VDEVICE(INTEL, 0x2821), board_ahci }, /* ICH8 */
-	{ PCI_VDEVICE(INTEL, 0x2822), board_ahci }, /* ICH8 */
+	{ PCI_VDEVICE(INTEL, 0x2822), board_ahci_nosntf }, /* ICH8 */
 	{ PCI_VDEVICE(INTEL, 0x2824), board_ahci }, /* ICH8 */
 	{ PCI_VDEVICE(INTEL, 0x2829), board_ahci }, /* ICH8M */
 	{ PCI_VDEVICE(INTEL, 0x282a), board_ahci }, /* ICH8M */
@@ -849,6 +859,12 @@ static void ahci_save_initial_config(str
 		cap &= ~HOST_CAP_PMP;
 	}
 
+	if ((cap & HOST_CAP_SNTF) && (hpriv->flags & AHCI_HFLAG_NO_SNTF)) {
+		dev_printk(KERN_INFO, &pdev->dev,
+			   "controller can't do SNTF, turning off CAP_SNTF\n");
+		cap &= ~HOST_CAP_SNTF;
+	}
+
 	if (pdev->vendor == PCI_VENDOR_ID_JMICRON && pdev->device == 0x2361 &&
 	    port_map != 1) {
 		dev_printk(KERN_INFO, &pdev->dev,


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