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

[Stefan Bader]

ACK, header looks good to me as well as the patch

Manoj Iyer wrote:
> 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


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