PATCH: Fix ide probe double detection

[Alan Cox <alan@redhat.com>]

Some devices don't decode master/slave - notably PCMCIA adapters. 
Unfortunately for us some also do, which makes it hard to guess if we
should probe the slave.

This patch fixes the problem by probing the slave and then using the model
and serial information to spot undecoded pairs. An additional check is done
to catch pairs of pre ATA devices just in case.

Alan


diff -u --new-file --recursive --exclude-from /usr/src/exclude linux-2.6.7/drivers/ide/ide-probe.c 2.6.7-ac/drivers/ide/ide-probe.c
--- linux-2.6.7/drivers/ide/ide-probe.c	2004-06-16 21:11:35.000000000 +0100
+++ 2.6.7-ac/drivers/ide/ide-probe.c	2004-06-16 21:19:28.000000000 +0100
@@ -749,6 +749,16 @@
 		ide_drive_t *drive = &hwif->drives[unit];
 		drive->dn = (hwif->channel ? 2 : 0) + unit;
 		(void) probe_for_drive(drive);
+		if (drive->present && hwif->present && unit == 1)
+		{
+			if(strcmp(hwif->drives[0].id->model, drive->id->model) == 0 &&
+			   strcmp(drive->id->model, "UNKNOWN") && /* Don't do this for non ATA or for noprobe */
+			   strncmp(hwif->drives[0].id->serial_no, drive->id->serial_no, 20) == 0)
+			{
+				printk(KERN_WARNING "ide-probe: ignoring undecoded slave\n");
+				drive->present = 0;
+			}
+		}
 		if (drive->present && !hwif->present) {
 			hwif->present = 1;
 			if (hwif->chipset != ide_4drives ||