Date:	Thu, 19 Jun 2008 11:34:12 +0200 (CEST)
From:	Geert Uytterhoeven <Geert.Uytterhoeven@...ycom.com>
To:	James Bottomley <James.Bottomley@...senPartnership.com>
cc:	linux-scsi@...r.kernel.org,
	Linux Kernel Development <linux-kernel@...r.kernel.org>
Subject: Re: [regression] CD-DA delay needed after insertion

On Wed, 18 Jun 2008, James Bottomley wrote:
> On Tue, 2008-06-17 at 15:31 +0200, Geert Uytterhoeven wrote:
> > On Mon, 16 Jun 2008, James Bottomley wrote:
> > > On Mon, 2008-06-16 at 17:05 +0200, Geert Uytterhoeven wrote:
> > > > On Sun, 15 Jun 2008, James Bottomley wrote:
> > > > > On Fri, 2008-06-13 at 13:57 +0200, Geert Uytterhoeven wrote:
> > > > > > We've found another regression in 2.6.25 w.r.t. CD media change on PS3.
> > > > > > 
> > > > > > It can easily be reproduced by:
> > > > > > 
> > > > > >   1. Inserting an audio CD
> > > > > >   2. Running the following command as soon as the blue CD/DVD/BD drive LED
> > > > > >      stops blinking and is lit continuously:
> > > > > >       
> > > > > > 	 cdparanoia -Z -q 1-1[:1] /dev/null || echo failed
> > > > > > 
> > > > > > On 2.6.25 (and current mainline), you have to wait ca. 10 seconds after
> > > > > > insertion, or it will fail.
> > > > > > On 2.6.24 and older, it just works immediately.
> > > > > > 
> > > > > > It does not matter whether
> > > > > > http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Fjejb%2Fscsi-rc-fixes-2.6.git;a=commitdiff_plain;h=d1daeabf0da5bfa1943272ce508e2ba785730bf0
> > > > > > is applied or not.
> > > > > > 
> > > > > > We haven't bisected it yet.
> > > > > 
> > > > > There aren't that many commits affecting sr between 2.6.24 and 2.6.25,
> > > > > so I'd bet on the previous culprits.
> > > > > 
> > > > > This time, the taxonomy looks like NOT_READY isn't being waited for
> > > > > properly.  I'd still tend to blame
> > > > > 210ba1d1724f5c4ed87a2ab1a21ca861a915f734 it's just that this time I
> > > > 
> > > > Reverting that commit doesn't fix the problem.
> > > 
> > > That's a bit of a problem.  Particularly as:
> > > 
> > > > > suspect this to be the problem line:
> > > > > 
> > > > > 	if (sshdr.sense_key == NOT_READY && sshdr.asc == 0x04)
> > > > > 		return CDS_DISC_OK;
> > > > > 
> > > > > Previously the code would have returned CDS_NO_DISC for the not ready
> > > > > case.  The CD would have tried to close the door but (and this is the
> > > > > key) it would have waited for the door to close before trying again.
> > > > 
> > > > I tried the patch below.
> > > > 
> > > > Now the kernel spits out messages every 2 seconds:
> > > > 
> > > > | G: CDS_NO_DISC
> > > > | G: CDS_NO_DISC
> > > > 
> > > > Insert CD-DA media
> > > > 
> > > > Reading from CD using cdparanioa fails
> > > > 
> > > > | F: CDS_DISC_OK
> > > > | F: CDS_DISC_OK
> > > > | F: CDS_DISC_OK
> > > > | F: CDS_DISC_OK
> > > > | F: CDS_DISC_OK
> > > 
> > > That's in the two lines I fingered as the source of the problem ...
> > > however, if reversing the apparently bad commit (that introduces those
> > > lines) doesn't work there's something else wrong.
> > > 
> > > Could you try altering your F: case to return CDS_DRIVE_NOT_READY, but
> > > if that doesn't work, it's going to take a bit of bisection, I'm
> > > afraid ...
> > 
> > Doesn't make any difference.
> > 
> > git-bisect taught me it was introduced by
> > 
> > commit 38582a62ecd337de4212004c7d4844899dc57890
> > Author: James Bottomley <James.Bottomley@...senPartnership.com>
> > Date:   Wed Feb 6 13:01:58 2008 -0600
> > 
> >     [SCSI] sr: fix test unit ready responses
> >     
> >     Commit 210ba1d1724f5c4ed87a2ab1a21ca861a915f734 updated sr.c to use
> >     the scsi_test_unit_ready() function.  Unfortunately, this has the
> >     wrong characteristic of eating NOT_READY returns which sr.c relies on
> >     for tray status.
> >     
> >     Fix by rolling an internal sr_test_unit_ready() that doesn't do this.
> 
> OK, that basically just replaced scsi_test_unit_ready with
> sr_test_unit_ready.  The only difference I can see is that
> scsi_test_unit_ready treats NOT_READY as a media change event and the
> new code doesn't.  This seems slightly wrong:  NOT_READY can indeed mean
> I have no medium, which is obviously what it's looking for.  However, it
> can also mean there's another command in progress.  If this is some type
> of write or format, you don't necessarily want the cd treating it as a
> disk change.
> 
> However, before we get into serious debugging, could you try this patch
> (applies over the previous fix for the capacity problem)?  I think it
> should restore the old not ready == medium change behaviour.
> 
> Thanks,
> 
> James
> 
> ---
> diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
> index c82df8b..a9acbc8 100644
> --- a/drivers/scsi/sr.c
> +++ b/drivers/scsi/sr.c
> @@ -179,7 +179,8 @@ int sr_test_unit_ready(struct scsi_device *sdev, struct scsi_sense_hdr *sshdr)
>  					      0, sshdr, SR_TIMEOUT,
>  					      retries--);
>  		if (scsi_sense_valid(sshdr) &&
> -		    sshdr->sense_key == UNIT_ATTENTION)
> +		    (sshdr->sense_key == UNIT_ATTENTION ||
> +		     sshdr->sense_key == NOT_READY))
>  			sdev->changed = 1;
>  
>  	} while (retries > 0 &&

Thanks, but unfortunately it doesn't help.

With kind regards,

Geert Uytterhoeven
Software Architect

Sony Techsoft Centre
The Corporate Village · Da Vincilaan 7-D1 · B-1935 Zaventem · Belgium

Phone:    +32 (0)2 700 8453
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E-mail:   Geert.Uytterhoeven@...ycom.com
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