From aa2371e980e7e8982292b23d6f0ce2d97da7c310 Mon Sep 17 00:00:00 2001
From: Tejun Heo <htejun@gmail.com>
Date: Mon, 10 Mar 2008 10:25:25 +0900
Subject: [PATCH] --- yaml --- r: 87423 b: refs/heads/master c:
 a22e64443f0aa4aa4e3c56a49e5c060e90752c07 h: refs/heads/master i:   87421:
 315737fcdf438f1ed1d312ce818984ef5beaa76d   87419:
 d01debb48ec4ebf849cc0996e5c75e63a7db5704   87415:
 78b9df2d4182313da0357cd2e6284644ea5c7f6f   87407:
 48fa072fe980f347934f378a87ea11fb8857cb92   87391:
 ab99768d75ab83548794972c037b6ba9d3f7624d   87359:
 ffd985ff2be6a8eddfdc11d6c0bed19773202cc2   87295:
 47bd6e8bbe3ee18cefebd4b2f67e30c4477aa494 v: v3

---
 [refs]                   |  2 +-
 trunk/drivers/ata/ahci.c | 48 ++++++++++++++++++++++++----------------
 2 files changed, 30 insertions(+), 20 deletions(-)

diff --git a/[refs] b/[refs]
index 398514b63b2b..5b10e9629b52 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: dea55137634226fd74d5187a15dee1244ec252cb
+refs/heads/master: a22e64443f0aa4aa4e3c56a49e5c060e90752c07
diff --git a/trunk/drivers/ata/ahci.c b/trunk/drivers/ata/ahci.c
index 53f5afd9420c..bbfccdbba3ab 100644
--- a/trunk/drivers/ata/ahci.c
+++ b/trunk/drivers/ata/ahci.c
@@ -49,6 +49,10 @@
 #define DRV_NAME	"ahci"
 #define DRV_VERSION	"3.0"
 
+static int ahci_skip_host_reset;
+module_param_named(skip_host_reset, ahci_skip_host_reset, int, 0444);
+MODULE_PARM_DESC(skip_host_reset, "skip global host reset (0=don't skip, 1=skip)");
+
 static int ahci_enable_alpm(struct ata_port *ap,
 		enum link_pm policy);
 static void ahci_disable_alpm(struct ata_port *ap);
@@ -1088,29 +1092,35 @@ static int ahci_reset_controller(struct ata_host *host)
 	ahci_enable_ahci(mmio);
 
 	/* global controller reset */
-	tmp = readl(mmio + HOST_CTL);
-	if ((tmp & HOST_RESET) == 0) {
-		writel(tmp | HOST_RESET, mmio + HOST_CTL);
-		readl(mmio + HOST_CTL); /* flush */
-	}
+	if (!ahci_skip_host_reset) {
+		tmp = readl(mmio + HOST_CTL);
+		if ((tmp & HOST_RESET) == 0) {
+			writel(tmp | HOST_RESET, mmio + HOST_CTL);
+			readl(mmio + HOST_CTL); /* flush */
+		}
 
-	/* reset must complete within 1 second, or
-	 * the hardware should be considered fried.
-	 */
-	ssleep(1);
+		/* reset must complete within 1 second, or
+		 * the hardware should be considered fried.
+		 */
+		ssleep(1);
 
-	tmp = readl(mmio + HOST_CTL);
-	if (tmp & HOST_RESET) {
-		dev_printk(KERN_ERR, host->dev,
-			   "controller reset failed (0x%x)\n", tmp);
-		return -EIO;
-	}
+		tmp = readl(mmio + HOST_CTL);
+		if (tmp & HOST_RESET) {
+			dev_printk(KERN_ERR, host->dev,
+				   "controller reset failed (0x%x)\n", tmp);
+			return -EIO;
+		}
 
-	/* turn on AHCI mode */
-	ahci_enable_ahci(mmio);
+		/* turn on AHCI mode */
+		ahci_enable_ahci(mmio);
 
-	/* some registers might be cleared on reset.  restore initial values */
-	ahci_restore_initial_config(host);
+		/* Some registers might be cleared on reset.  Restore
+		 * initial values.
+		 */
+		ahci_restore_initial_config(host);
+	} else
+		dev_printk(KERN_INFO, host->dev,
+			   "skipping global host reset\n");
 
 	if (pdev->vendor == PCI_VENDOR_ID_INTEL) {
 		u16 tmp16;