linux-kernel - Re: READ CAPACITY (16) failing

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Date:	Fri, 10 Apr 2009 15:28:38 -0700
From:	James Bottomley <James.Bottomley@...senPartnership.com>
To:	"Mike Miller (OS Dev)" <mikem@...rdog.cca.cpqcorp.net>
Cc:	Matthew Wilcox <matthew@....cx>,
	LKML-SCSI <linux-scsi@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>, mike.miller@...com
Subject: Re: READ CAPACITY (16) failing

On Fri, 2009-04-10 at 14:31 -0500, Mike Miller (OS Dev) wrote:
> On Wed, Apr 08, 2009 at 01:54:48PM -0600, Matthew Wilcox wrote:
> > On Wed, Apr 08, 2009 at 02:43:57PM -0500, Mike Miller (OS Dev) wrote:
> > > I'm working on the HP Smart Array SCSI driver (hpsa) and I'm seeing the
> > > following failures:
> > > 
> > > hpsa1: <0x3230> at PCI 0000:02:00.0 IRQ 76 using DAC
> > > scsi4 : hpsa
> > > scsi 4:0:0:0: Direct-Access     HP       LOGICAL VOLUME   5.20 PQ: 0 ANSI: 5
> > > sd 4:0:0:0: Attached scsi generic sg4 type 0
> > > sd 4:0:0:0: [sdd] READ CAPACITY(16) failed
> > > sd 4:0:0:0: [sdd] Result: hostbyte=DID_ABORT driverbyte=DRIVER_OK
> > > sd 4:0:0:0: [sdd] Sense not available.
> > > hpsa: cp ffff8800cf400000 has check condition: unknown type: Sense: 0x5,
> > > ASC: 0x20, ASCQ: 0x0, Returning result: 0x2, cmd=[a0 00 00 00 00 00 00 00 10
> > > 00]
> > 
> > > The READ CAPACITY failures are what I'm concerned about. I can't seem to track
> > > down why that's failing.
> > > I've tried printing out the_result from sd but it's not printing out. I'm
> > > assuming that anytime I load the driver it goes thru sd.
> > > 
> > > 	if (the_result) {
> > > 		sense_valid = scsi_sense_valid(&sshdr);
> > > 		if (sense_valid &&
> > > 			sshdr.sense_key == ILLEGAL_REQUEST &&
> > > 			(sshdr.asc == 0x20 || sshdr.asc == 0x24) &&
> > > 			sshdr.ascq == 0x00)
> > > 			/* Invalid Command Operation Code or
> > > 			 * Invalid Field in CDB, just retry
> > > 			 * silently with RC10 */
> > > 			return -EINVAL;
> > > 		}
> > > 	retries--;
> > > 	} while (the_result && retries);
> > > 	printk(KERN_WARNING "sd-mfm: the_result = %d\n", the_result);
> > 
> > Probably the device you're testing against doesn't support RC16, which
> > is fine.  But for some reason, we're not getting valid sense data back
> > from the device.  Now, there's two responses to this that seem rational
> > to me:
> > 
> >  - In sd.c, if the drive has returned no/invalid sense data, try RC10
> >    silently, just like the 0x20 / 0x24 ASC case.
> >  - Find out why this drive doesn't report valid sense data when attached
> >    to hpsa.  I assume it does report valid sense data when attached to
> >    some other scsi card?
> 
> Me again,
> The controllers do support RC16. After some more work it looks like RC16 is
> never getting to the driver. I'm snooping the CDB's of all requests as well
> as the completions from the driver and I never see a 0x9e. I do see the
> RC10 (0x25) though, so I think my debug is right.
> 
> Why would I never the see the command in the driver?

Because your devices are reporting compliance to a standard before RC16
was implemented (we have a check in sd_try_rc16_first() to see if you
comply to higher than SBC-2).  Then, after you've failed this, if you
don't return the conventional 0xffffffff to RC10, we never retry with
RC16.

James


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