Date: Mon, 20 May 2002 16:20:03 -0700 (PDT) From: Matthias Andree <matthias.andree@web.de> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/37060: kernel panic with hw.ata.tags=1 in ata-disk.c:710 Message-ID: <200205202320.g4KNK3802608@freefall.freebsd.org>
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The following reply was made to PR kern/37060; it has been noted by GNATS.
From: Matthias Andree <matthias.andree@web.de>
To: freebsd-gnats-submit@FreeBSD.org,
ma@dt.e-technik.uni-dortmund.de, sos@freebsd.org,
Andrew Gallatin <gallatin@cs.duke.edu>
Cc:
Subject: Re: kern/37060: kernel panic with hw.ata.tags=1 in ata-disk.c:710
Date: Tue, 21 May 2002 01:17:27 +0200
I believe I know now what's going on.
ata_raiddisk_attach in ata-disk.c:218 (ad_attach()) tries to read a RAID
signature from the newly detected drive. In my case, that's ad1, the
secondary master. At that time, ad0 (primary master) and ad1 are known,
ad2 is not.
217 /* if this disk belongs to an ATA RAID dont print the probe */
218 if (ata_raiddisk_attach(adp))
219 adp->flags |=3D AD_F_RAID_SUBDISK;
220 else
221 ad_print(adp);
222 }
now, ata_raiddisk_attach uses ar_rw, which calls upon ata_start, ata-all.c:=
661.
675 s =3D splbio();
676 #if NATADISK > 0
677 /* find & call the responsible driver if anything on the ATA qu=
eue *
/
678 if (TAILQ_EMPTY(&ch->ata_queue)) {
679 if (ch->devices & (ATA_ATA_MASTER) && ch->device[MASTER].dr=
iver)
680 ad_start(&ch->device[MASTER]);
681 if (ch->devices & (ATA_ATA_SLAVE) && ch->device[SLAVE].driv=
er)
682 ad_start(&ch->device[SLAVE]);
683 }
684 if ((ad_request =3D TAILQ_FIRST(&ch->ata_queue))) {
685 TAILQ_REMOVE(&ch->ata_queue, ad_request, chain);
686 ch->active =3D ATA_ACTIVE_ATA;
687 ch->running =3D ad_request;
688 if (ad_transfer(ad_request) =3D=3D ATA_OP_CONTINUES) {
689 splx(s);
690 return;
691 }
692 }
ata_start knows it has no driver for the slave yet (ad2, secondary
slave, has not yet been probed).
However, in l. 688, ad_transfer is called, which itself (ata-disk.c:495)
calls ad_service:
469 if (adp->device->mode >=3D ATA_DMA &&
470 !ata_dmasetup(adp->device->channel, adp->device->unit,
471 request->dmatab, request->data, request->=
bytecount)) {
472 request->flags |=3D ADR_F_DMA_USED;
473 request->currentsize =3D request->bytecount;
474 =20
475 /* do we have tags enabled ? */
476 if (adp->flags & AD_F_TAG_ENABLED) {
=2E..
491 /* if ATA bus RELEASE check for SERVICE */
492 if (adp->flags & AD_F_TAG_ENABLED &&
493 ATA_INB(adp->device->channel->r_io, ATA_IREASON=
) &
494 ATA_I_RELEASE)
495 return ad_service(adp, 1);
ad_service now tries to figure the slave flags at lines 710-713 and
failes because adp->device->channel->device[0] is uninitialized yet is.
I'm not sure as to what the proper fix is, as I don't understand the
"change" flag and its implications.
However, I set a breakpoint at line #706, and on the first five hits, I
issued "set change=3D0" and "c", and the drives probed fine. I then
removed the breakpoint and checked what the system would do: it booted
up fine.
702 int
703 ad_service(struct ad_softc *adp, int change)
704 {
705 /* do we have to check the other device on this channel ? */
706 if (adp->device->channel->flags & ATA_QUEUED && change) {
707 int device =3D adp->device->unit;
708 =20
709 if (adp->device->unit =3D=3D ATA_MASTER) {
710 if (adp->device->channel->devices & ATA_ATA_SLAVE &&
711 ((struct ad_softc *)
712 (adp->device->channel->
713 device[ATA_DEV(ATA_SLAVE)].driver))->flags&AD_F_T=
AG_EN
ABLED)
714 device =3D ATA_SLAVE;
=2E..
732 adp->device->channel->status =3D
733 ATA_INB(adp->device->channel->r_altio, ATA_ALTSTAT);
734 =20
735 /* do we have a SERVICE request from the drive ? */
736 if (adp->flags & AD_F_TAG_ENABLED &&
737 adp->outstanding > 0 &&
=2E..
I'm not sure what the proper fix to this is, if it is to temporary
disable Tagged Queueing until all drives are probed, fix ad_service to
set change =3D 0 locally when the other drive is uninitialized, whatever.
With the "set change =3D 0" gdb intervention, here's the ATA dmesg:
atapci0: <VIA 82C686 ATA66 controller> port 0xffa0-0xffaf at device 7.1 on =
pci0
ata0: iobase=3D0x01f0 altiobase=3D0x03f6 bmaddr=3D0xffa0
ata0: mask=3D03 ostat0=3D50 ostat2=3D00
ata0-master: ATAPI 00 00
ata0-slave: ATAPI 00 00
ata0: mask=3D03 stat0=3D50 stat1=3D00
ata0-master: ATA 01 a5
ata0: devices=3D01
ata0: at 0x1f0 irq 14 on atapci0
ata1: iobase=3D0x0170 altiobase=3D0x0376 bmaddr=3D0xffa8
ata1: mask=3D03 ostat0=3D50 ostat2=3D50
ata1-master: ATAPI 00 00
ata1-slave: ATAPI 00 00
ata1: mask=3D03 stat0=3D50 stat1=3D50
ata1-master: ATA 01 a5
ata1-slave: ATA 01 a5
ata1: devices=3D03
ata1: at 0x170 irq 15 on atapci0
=2E..
ad0: success setting UDMA4 on VIA chip
Creating DISK ad0
ar: FreeBSD check1 failed
ad0: <Maxtor 4W060H4/AAH41310> ATA-6 disk at ata0-master
ad0: 58610MB (120033900 sectors), 119081 C, 16 H, 63 S, 512 B
ad0: 16 secs/int, 1 depth queue, UDMA66
ad0: piomode=3D4 dmamode=3D2 udmamode=3D5 cblid=3D1
ad1: success setting UDMA4 on VIA chip
Creating DISK ad1
ar: FreeBSD check1 failed
ad1: <IBM-DTLA-307045/TX6OA6AA> ATA-5 disk at ata1-master
ad1: 43979MB (90069840 sectors), 89355 C, 16 H, 63 S, 512 B
ad1: 16 secs/int, 32 depth queue, tagged UDMA66
ad1: piomode=3D4 dmamode=3D2 udmamode=3D5 cblid=3D1
ad2: success setting UDMA4 on VIA chip
Creating DISK ad2
ar: FreeBSD check1 failed
ad2: <WDC AC420400D/J58OA30K> ATA-4 disk at ata1-slave
ad2: 19470MB (39876480 sectors), 39560 C, 16 H, 63 S, 512 B
ad2: 16 secs/int, 1 depth queue, UDMA66
ad2: piomode=3D4 dmamode=3D2 udmamode=3D4 cblid=3D1
=2E..
[on with SCSI probes]
Nothing is mounted from ad1, and I want an "OK" from S=F8ren before I try
to use ad1 with the "set change=3D0" during the bootup to see if tagged
queueing actually works.
--=20
Matthias Andree
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