ide: change master/slave IDENTIFY order

Need to probe slave device first to make it release PDIAG-
(this is required for correct device side cable detection).

Based on libata commit f31f0cc2f0b7527072d94d02da332d9bb8d7d94c.

Thanks to Craig for testing this patch.

Cc: Craig Block <chblock3@yahoo.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

2 files changed, 3 insertions, 5 deletions

diff --git a/drivers/ide/ide-iops.c b/drivers/ide/ide-iops.c
index f5e73e2950d4..bb691f2eb5bf 100644
--- a/drivers/ide/ide-iops.c
+++ b/drivers/ide/ide-iops.c
@@ -613,7 +613,6 @@ u8 eighty_ninty_three (ide_drive_t *drive)
 
         /*
          * FIXME:
-         * - change master/slave IDENTIFY order
          * - force bit13 (80c cable present) check also for !ivb devices
          *   (unless the slave device is pre-ATA3)
          */
diff --git a/drivers/ide/ide-probe.c b/drivers/ide/ide-probe.c
index b4c9f63a3854..d1011712601c 100644
--- a/drivers/ide/ide-probe.c
+++ b/drivers/ide/ide-probe.c
@@ -719,9 +719,9 @@ EXPORT_SYMBOL_GPL(ide_undecoded_slave);
  */
 static void probe_hwif(ide_hwif_t *hwif, void (*fixup)(ide_hwif_t *hwif))
 {
-        unsigned int unit;
         unsigned long flags;
         unsigned int irqd;
+        int unit;
 
         if (hwif->noprobe)
                 return;
@@ -777,10 +777,9 @@ static void probe_hwif(ide_hwif_t *hwif, void (*fixup)(ide_hwif_t *hwif))
                 printk(KERN_DEBUG "%s: Wait for ready failed before probe !\n", hwif->name);
 
         /*
-         * Second drive should only exist if first drive was found,
-         * but a lot of cdrom drives are configured as single slaves.
+         * Need to probe slave device first to make it release PDIAG-.
          */
-        for (unit = 0; unit < MAX_DRIVES; ++unit) {
+        for (unit = MAX_DRIVES - 1; unit >= 0; unit--) {
                 ide_drive_t *drive = &hwif->drives[unit];
                 drive->dn = (hwif->channel ? 2 : 0) + unit;
                 (void) probe_for_drive(drive);