Re: [PATCH] remove dead ATAPI multi-lun support (used for ide-scsi)

On 2004.02.20 16:47, Bartlomiej Zolnierkiewicz wrote:

[IDE] remove dead ATAPI multi-lun support (used for ide-scsi)

ChangeSet@1.889.69.2 03-01-23 14:51:03-05:00  adam@yggdrasil.com
|  The following changes to ide-scsi.c are a recovery of the
| changes that I had in ide-scsi.c in the stock kernel's before
| Martin Dalecki's IDE tree was reverted and a few other changes.
...

broke it.

Before this change drive->id->last_id & 0x7 was used as shost->max_lun
and "hdXlun=" kernel parameter could be used to override it.

It was needed probably only for some rare ATAPI PD-CD drives
(http://www.geocrawler.com/archives/3/58/1999/11/50/2877161/).

However it was far from optimal:
- people played with "hdXlun=" and then complained about multiple instances
  of the same device (most ATAPI drives respond to each LUN)
- probably some devices return 7 not 0 in id->last_id (=> 7 x same device)

This patch cleans things up, multi-lun will be fixed if needed in ide-scsi.
I think that this may work but can't verify it:

	if (id->last_lun && id->last_lun != 7)
		shost->max_lun = id->last_lun + 1;
	else
		shost->max_lun = 1;

I have verified that this works with my PD/CD drive, the patch to ide-scsi.c
that I suggest (against linux-2.6.4-rc1-mm2) is below.

Thanks, Willem Riede.

--- m0/drivers/scsi/ide-scsi.c	2004-03-05 19:54:33.000000000 -0500
+++ m1/drivers/scsi/ide-scsi.c	2004-03-06 14:49:47.000000000 -0500

@@ -1148,7 +1148,16 @@
 		return 1;
 
 	host->max_id = 1;
-	host->max_lun = 1;
+
+#if IDESCSI_DEBUG_LOG
+	if (drive->id->last_lun)
+		printk(KERN_NOTICE "%s: id->last_lun=%u\n", drive->name, drive->id->last_lun);
+#endif
+	if ((drive->id->last_lun & 0x7) != 7)
+		host->max_lun = (drive->id->last_lun & 0x7) + 1;
+	else
+		host->max_lun = 1;
+
 	drive->driver_data = host;
 	idescsi = scsihost_to_idescsi(host);
 	idescsi->drive = drive;

Willem Riede wrote:

On 2004.02.20 16:47, Bartlomiej Zolnierkiewicz wrote:

quoted

[IDE] remove dead ATAPI multi-lun support (used for ide-scsi)

ChangeSet@1.889.69.2 03-01-23 14:51:03-05:00  adam@yggdrasil.com
|  The following changes to ide-scsi.c are a recovery of the
| changes that I had in ide-scsi.c in the stock kernel's before
| Martin Dalecki's IDE tree was reverted and a few other changes.
...

broke it.

Before this change drive->id->last_id & 0x7 was used as shost->max_lun
and "hdXlun=" kernel parameter could be used to override it.

It was needed probably only for some rare ATAPI PD-CD drives
(http://www.geocrawler.com/archives/3/58/1999/11/50/2877161/).

However it was far from optimal:
- people played with "hdXlun=" and then complained about multiple instances
 of the same device (most ATAPI drives respond to each LUN)
- probably some devices return 7 not 0 in id->last_id (=> 7 x same device)

This patch cleans things up, multi-lun will be fixed if needed in ide-scsi.
I think that this may work but can't verify it:

if (id->last_lun && id->last_lun != 7)
	shost->max_lun = id->last_lun + 1;
else
	shost->max_lun = 1;

I have verified that this works with my PD/CD drive, the patch to ide-scsi.c
that I suggest (against linux-2.6.4-rc1-mm2) is below.

I have a multi-LUN ATAPI CD changer here...

	Jeff