[JAUNTY] SRU: UBUNTU: libata: handle SEMB signature better

[Manoj Iyer]

SRU JUSTIFICATION:

IMPACT:  Western Digital Caviar SE SATA 2nd Generation Hard Drive is not 
recognized by the kernel.

FIX: Make ata_dev_classify() report ATA_DEV_SEMB on the
     sig and let ata_dev_read_id() work around it by trying IDENTIFY once.

TEST: Originator of the bug has tested the kernel in 
http://people.ubuntu.com/~manjo/lp257790-jaunty/ and reported it works.

The following changes since commit 
a63b7d7beeaa1f8f33369cab6419831fa8991e40:
   Tyler Hicks (1):
         UBUNTU: SAUCE: (drop after 2.6.28) [PATCH] eCryptfs: Larger buffer 
for encrypted symlink targets

are available in the git repository at:

   git://kernel.ubuntu.com/manjo/ubuntu-jaunty.git lp257790

Tejun Heo (1):
       UBUNTU: libata: handle SEMB signature better

  drivers/ata/libata-core.c |   18 ++++++++++++++++--
  1 files changed, 16 insertions(+), 2 deletions(-)


>From c21f5bb8fd1150e2006eee17a056723083970a45 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj at kernel.org>
Date: Wed, 15 Apr 2009 06:21:10 +0900
Subject: [PATCH] UBUNTU: libata: handle SEMB signature better

BUG: #257790
BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/257790

WDC WD1600JS-62MHB5 successfully hits the window between ATA/ATAPI-7
and Serial ATA II standards and reports 3c/c3 signature which now is
assigned to SEMB.  Make ata_dev_classify() report ATA_DEV_SEMB on the
sig and let ata_dev_read_id() work around it by trying IDENTIFY once.

This fixes bko#11579.

Signed-off-by: Tejun Heo <tj at kernel.org>
Reported-by: David Haun <drhaun88 at gmail.com>
Reported-by: Lars Wirzenius <liw at liw.fi>
Reported-by: Juan Manuel <jmcarranza at gmail.com>
Signed-off-by: Jeff Garzik <jgarzik at redhat.com>
Signed-off-by: Manoj Iyer <manoj.iyer at canonical.com>

Author:    Tejun Heo <tj at kernel.org>
---
  drivers/ata/libata-core.c |   18 ++++++++++++++++--
  1 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 3366993..9844eb6 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1159,6 +1159,9 @@ unsigned int ata_dev_classify(const struct ata_taskfile *tf)
  	 *
  	 * We follow the current spec and consider that 0x69/0x96
  	 * identifies a port multiplier and 0x3c/0xc3 a SEMB device.
+	 * Unfortunately, WDC WD1600JS-62MHB5 (a hard drive) reports
+	 * SEMB signature.  This is worked around in
+	 * ata_dev_read_id().
  	 */
  	if ((tf->lbam == 0) && (tf->lbah == 0)) {
  		DPRINTK("found ATA device by sig\n");
@@ -1176,8 +1179,8 @@ unsigned int ata_dev_classify(const struct ata_taskfile *tf)
  	}

  	if ((tf->lbam == 0x3c) && (tf->lbah == 0xc3)) {
-		printk(KERN_INFO "ata: SEMB device ignored\n");
-		return ATA_DEV_SEMB_UNSUP; /* not yet */
+		DPRINTK("found SEMB device by sig (could be ATA device)\n");
+		return ATA_DEV_SEMB;
  	}

  	DPRINTK("unknown device\n");
@@ -2004,6 +2007,7 @@ int ata_dev_read_id(struct ata_device *dev, unsigned int *p_class,
  	struct ata_taskfile tf;
  	unsigned int err_mask = 0;
  	const char *reason;
+	bool is_semb = class == ATA_DEV_SEMB;
  	int may_fallback = 1, tried_spinup = 0;
  	int rc;

@@ -2014,6 +2018,8 @@ retry:
  	ata_tf_init(dev, &tf);

  	switch (class) {
+	case ATA_DEV_SEMB:
+		class = ATA_DEV_ATA;	/* some hard drives report SEMB sig */
  	case ATA_DEV_ATA:
  		tf.command = ATA_CMD_ID_ATA;
  		break;
@@ -2050,6 +2056,14 @@ retry:
  			return -ENOENT;
  		}

+		if (is_semb) {
+			ata_dev_printk(dev, KERN_INFO, "IDENTIFY failed on "
+				       "device w/ SEMB sig, disabled\n");
+			/* SEMB is not supported yet */
+			*p_class = ATA_DEV_SEMB_UNSUP;
+			return 0;
+		}
+
  		if ((err_mask == AC_ERR_DEV) && (tf.feature & ATA_ABORTED)) {
  			/* Device or controller might have reported
  			 * the wrong device class.  Give a shot at the
-- 
1.6.0.4


Cheers
--- manjo