From be2bb06e6d31e67259b43d6a6cda8082505e9a28 Mon Sep 17 00:00:00 2001
From: Mark Lord <liml@rtr.ca>
Date: Thu, 19 Mar 2009 13:32:21 -0400
Subject: [PATCH] --- yaml --- r: 133598 b: refs/heads/master c:
 e18086d69cb5bb864749a0637f6ac573aa89d5ea h: refs/heads/master v: v3

---
 [refs]                          |  2 +-
 trunk/drivers/ata/libata-core.c | 13 +++++++++++--
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/[refs] b/[refs]
index baf6a7f00da9..65edbdb0c39f 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 000b344f4ca7828ee43940255c8bbb32e2c7dbec
+refs/heads/master: e18086d69cb5bb864749a0637f6ac573aa89d5ea
diff --git a/trunk/drivers/ata/libata-core.c b/trunk/drivers/ata/libata-core.c
index d4a7b8a96ecd..e7ea77cf6069 100644
--- a/trunk/drivers/ata/libata-core.c
+++ b/trunk/drivers/ata/libata-core.c
@@ -57,6 +57,7 @@
 #include <linux/scatterlist.h>
 #include <linux/io.h>
 #include <linux/async.h>
+#include <linux/log2.h>
 #include <scsi/scsi.h>
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_host.h>
@@ -2389,6 +2390,7 @@ int ata_dev_configure(struct ata_device *dev)
 	dev->cylinders = 0;
 	dev->heads = 0;
 	dev->sectors = 0;
+	dev->multi_count = 0;
 
 	/*
 	 * common ATA, ATAPI feature tests
@@ -2426,8 +2428,15 @@ int ata_dev_configure(struct ata_device *dev)
 
 		dev->n_sectors = ata_id_n_sectors(id);
 
-		if (dev->id[59] & 0x100)
-			dev->multi_count = dev->id[59] & 0xff;
+		/* get current R/W Multiple count setting */
+		if ((dev->id[47] >> 8) == 0x80 && (dev->id[59] & 0x100)) {
+			unsigned int max = dev->id[47] & 0xff;
+			unsigned int cnt = dev->id[59] & 0xff;
+			/* only recognize/allow powers of two here */
+			if (is_power_of_2(max) && is_power_of_2(cnt))
+				if (cnt <= max)
+					dev->multi_count = cnt;
+		}
 
 		if (ata_id_has_lba(id)) {
 			const char *lba_desc;