From 5880b5de7101cc123778c5d17d4f3986351f3122 Mon Sep 17 00:00:00 2001
From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Date: Mon, 15 Jun 2009 18:52:54 +0200
Subject: [PATCH] ide: don't enable IORDY at a probe time

* Add 'unsigned long port_flags' field to ide_hwif_t.

* Add IDE_PFLAG_PROBING port flag and keep it set during probing.

* Fix ide_pio_need_iordy() to not enable IORDY at a probe time
  (IORDY may lead to controller lock up on certain controllers
   if the port is not occupied).

Loosely based on the recent libata's fix by Tejun, thanks to Alan
for the hint that IDE may also need it.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
---
 drivers/ide/ide-probe.c     | 16 +++++++++++++++-
 drivers/ide/ide-xfer-mode.c |  6 ++++++
 include/linux/ide.h         |  6 ++++++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/ide/ide-probe.c b/drivers/ide/ide-probe.c
index f371b0de314..fdd04bcd556 100644
--- a/drivers/ide/ide-probe.c
+++ b/drivers/ide/ide-probe.c
@@ -1378,6 +1378,9 @@ int ide_host_register(struct ide_host *host, const struct ide_port_info *d,
 
 		ide_init_port(hwif, i & 1, d);
 		ide_port_cable_detect(hwif);
+
+		hwif->port_flags |= IDE_PFLAG_PROBING;
+
 		ide_port_init_devices(hwif);
 	}
 
@@ -1388,6 +1391,8 @@ int ide_host_register(struct ide_host *host, const struct ide_port_info *d,
 		if (ide_probe_port(hwif) == 0)
 			hwif->present = 1;
 
+		hwif->port_flags &= ~IDE_PFLAG_PROBING;
+
 		if ((hwif->host_flags & IDE_HFLAG_4DRIVES) == 0 ||
 		    hwif->mate == NULL || hwif->mate->present == 0) {
 			if (ide_register_port(hwif)) {
@@ -1569,11 +1574,20 @@ EXPORT_SYMBOL_GPL(ide_host_remove);
 
 void ide_port_scan(ide_hwif_t *hwif)
 {
+	int rc;
+
 	ide_port_apply_params(hwif);
 	ide_port_cable_detect(hwif);
+
+	hwif->port_flags |= IDE_PFLAG_PROBING;
+
 	ide_port_init_devices(hwif);
 
-	if (ide_probe_port(hwif) < 0)
+	rc = ide_probe_port(hwif);
+
+	hwif->port_flags &= ~IDE_PFLAG_PROBING;
+
+	if (rc < 0)
 		return;
 
 	hwif->present = 1;
diff --git a/drivers/ide/ide-xfer-mode.c b/drivers/ide/ide-xfer-mode.c
index 0b47ca13907..46d203ce60c 100644
--- a/drivers/ide/ide-xfer-mode.c
+++ b/drivers/ide/ide-xfer-mode.c
@@ -109,6 +109,12 @@ EXPORT_SYMBOL_GPL(ide_get_best_pio_mode);
 
 int ide_pio_need_iordy(ide_drive_t *drive, const u8 pio)
 {
+	/*
+	 * IORDY may lead to controller lock up on certain controllers
+	 * if the port is not occupied.
+	 */
+	if (pio == 0 && (drive->hwif->port_flags & IDE_PFLAG_PROBING))
+		return 0;
 	return ata_id_pio_need_iordy(drive->id, pio);
 }
 EXPORT_SYMBOL_GPL(ide_pio_need_iordy);
diff --git a/include/linux/ide.h b/include/linux/ide.h
index 8c7f5e50e91..8771d49aa87 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -661,6 +661,10 @@ struct ide_dma_ops {
 	u8	(*dma_sff_read_status)(struct hwif_s *);
 };
 
+enum {
+	IDE_PFLAG_PROBING		= (1 << 0),
+};
+
 struct ide_host;
 
 typedef struct hwif_s {
@@ -677,6 +681,8 @@ typedef struct hwif_s {
 
 	ide_drive_t	*devices[MAX_DRIVES + 1];
 
+	unsigned long	port_flags;
+
 	u8 major;	/* our major number */
 	u8 index;	/* 0 for ide0; 1 for ide1; ... */
 	u8 channel;	/* for dual-port chips: 0=primary, 1=secondary */