Re: 2.6.27-rc1 (2fca5c): libata: kernel cant boot

[Jens Axboe <jens.axboe@oracle.com>]

On Fri, Oct 24 2008, Jens Axboe wrote:
> On Fri, Oct 24 2008, Alexander Beregalov wrote:
> > Hi
> > 
> > commit 2fca5ccf97d2c28bcfce44f5b07d85e74e3cd18e
> > Author: Jens Axboe <jens.axboe@oracle.com>
> > Date:   Wed Oct 22 09:34:49 2008 +0200
> > 
> >     libata: switch to using block layer tagging support
> > 
> > 
> > This kernel can not read even 0 sector on disk with rootfs. It
> > initialized disk, but cant read it at all.
> >  CMD646 on Sparc
> > 
> > Rverting helped.
> 
> Doh, how annoying! What driver does that controller use? PATA doesn't
> even use NCQ, so it's a bit of an oddity that it makes a difference at
> all.
> 
> Can you provide the boot messages?

Darn, this smells like a train wreck. I'm assuming this fixes it?

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index d5b9b72..461ef5e 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -708,7 +708,11 @@ static struct ata_queued_cmd *ata_scsi_qc_new(struct ata_device *dev,
 {
 	struct ata_queued_cmd *qc;
 
-	qc = ata_qc_new_init(dev, cmd->request->tag);
+	if (cmd->request->tag != -1)
+		qc = ata_qc_new_init(dev, cmd->request->tag);
+	else
+		qc = ata_qc_new_init(dev, 0);
+		
 	if (qc) {
 		qc->scsicmd = cmd;
 		qc->scsidone = done;

-- 
Jens Axboe