Re: [PATCH linux-2.6.13-rc3] Mod15Write quirk against v2.6.13

[Jeff Garzik <jgarzik@pobox.com>]

Tejun Heo wrote:
>  sata_sil Mod15Write workaround was broken by the following commit by
> Albert Lee.
> 
> Commit: 21b1ed74ee3667dcabcba92e486988ea9119a085
> [PATCH] libata: Prevent the interrupt handler from completing a command twice
> 
>  This commit clears ATA_QCFLAG_ACTIVE in ata_qc_complete() and doesn't
> handle IRQ if ATA_QCFLAG_ACTIVE is cleared on entry to interrupt
> routine.  As m15w workaround executes single command multiple times,
> the flag is cleared after the first chunk completion and the following
> interrupt gets ignored resulting in "nobody cared" interrupt error.
> 
>  The following changes are made in m15w workaround to fix this.
> 
>  * Moved clearing of ATA_QCFLAG_ACTIVE before invoking ->complete_fn,
>    so that ->complete_fn can mangle with the flag.  This doesn't affect
>    any users.
>  * Added setting ATA_QCFLAG_ACTIVE in m15w chunk completion function.

> diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
> --- a/drivers/scsi/libata-core.c
> +++ b/drivers/scsi/libata-core.c
> @@ -3087,8 +3087,8 @@ void ata_qc_complete(struct ata_queued_c
>  		ata_sg_clean(qc);
>  
>  	/* call completion callback */
> -	rc = qc->complete_fn(qc, drv_stat);
>  	qc->flags &= ~ATA_QCFLAG_ACTIVE;
> +	rc = qc->complete_fn(qc, drv_stat);
>  
>  	/* if callback indicates not to complete command (non-zero),
>  	 * return immediately


I'm leaning towards applying latest Albert's ATA_QCFLAG_ACTIVE fix, 
which does the same thing your patch did.

For various complex tasks in the SCSI translation layer (SAT), we may 
wish to issue multiple ATA commands, before signalling completion.  As 
your mod15write patch is an example of this, it helps point out what 
parts of libata need work in order to accomplish this.

Any comments before I apply Albert's patch?

	Jeff