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From: Sergei Shtylyov <sshtylyov@ru.mvista.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: jgarzik@pobox.com, linux-ide@vger.kernel.org, akpm@osdl.org
Subject: Re: [PATCH] libata-core: Don't have screaming fits over DF/ERR combinations
Date: Mon, 15 Oct 2007 23:53:45 +0400	[thread overview]
Message-ID: <4713C549.6010704@ru.mvista.com> (raw)
In-Reply-To: <20071015192313.5892ed42@the-village.bc.nu>

Alan Cox wrote:

> Some hardware seems to get this wrong in a non-harmful way, and there are
> some devices that seem to do it deliberately for various reasons.

> Just take it as a device error not a catastrophic state machine
> explosion. 

> Signed-off-by: Alan Cox <alan@redhat.com>
> 
> diff -u --exclude-from /usr/src/exclude --new-file --recursive linux.vanilla-2.6.23-mm1/drivers/ata/libata-core.c linux-2.6.23-mm1/drivers/ata/libata-core.c
> --- linux.vanilla-2.6.23-mm1/drivers/ata/libata-core.c	2007-10-15 15:03:26.000000000 +0100
> +++ linux-2.6.23-mm1/drivers/ata/libata-core.c	2007-10-15 15:13:49.000000000 +0100
> @@ -5258,7 +5319,15 @@
>  		if (unlikely(status & (ATA_ERR | ATA_DF))) {
>  			ata_port_printk(ap, KERN_WARNING, "DRQ=1 with device "
>  					"error, dev_stat 0x%X\n", status);
> -			qc->err_mask |= AC_ERR_HSM;
> +			/* Some devices muck this up. Some follow an ATA
> +			   non-standard that permits the damaged sector to
> +			   be retrieved at this point. The ATA spec says
> +			   we should jump up and down on DRQ + ERR, reality

    I've always thought that setting both DRQ and ERR is perfectly valid 
(well, maybe it's become invalid since ATAPI-4 where all these state 
transition flow charts have made its first appearance, to be quickly replaced 
by the state diagrams :-) -- I'm too lazy to check now... :-)

> +			   says we should be a little more relaxed.
> +
> +			   Rather than an HSM error, take it as a device
> +			   error */

    I'm not sure it's an error in the first place.

> +			qc->err_mask |= AC_ERR_DEV;
>  			ap->hsm_task_state = HSM_ST_ERR;
>  			goto fsm_start;
>  		}

MBR, Sergei

  reply	other threads:[~2007-10-15 19:53 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-10-15 18:23 [PATCH] libata-core: Don't have screaming fits over DF/ERR combinations Alan Cox
2007-10-15 19:53 ` Sergei Shtylyov [this message]
2007-10-15 20:02   ` Jeff Garzik
2007-10-15 20:05     ` Sergei Shtylyov
2007-10-15 20:09       ` Jeff Garzik
2007-10-15 20:58         ` Alan Cox
2007-10-25  6:04 ` Jeff Garzik

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