[SCSI] mac_esp: fix PIO mode, take 2

The mac_esp PIO algorithm no longer works in 2.6.31 and crashes my Centris
660av. So here's a better one.

Also, force async with esp_set_offset() rather than esp_slave_configure().

One of the SCSI drives I tested still doesn't like the PIO mode and fails
with "esp: esp0: Reconnect IRQ2 timeout" (the same drive works fine in
PDMA mode).

This failure happens when esp_reconnect_with_tag() tries to read in two
tag bytes but the chip only provides one (0x20). I don't know what causes
this. I decided not to waste any more time trying to fix it because the
best solution is to rip out the PIO mode altogether and use the DMA
engine.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 4 insertions, 10 deletions

diff --git a/drivers/scsi/esp_scsi.c b/drivers/scsi/esp_scsi.c
index a680e18b5f3b..e2bc779f86c1 100644
--- a/drivers/scsi/esp_scsi.c
+++ b/drivers/scsi/esp_scsi.c
@@ -1449,9 +1449,6 @@ static void esp_msgin_sdtr(struct esp *esp, struct esp_target_data *tp)
 	if (offset > 15)
 		goto do_reject;
 
-	if (esp->flags & ESP_FLAG_DISABLE_SYNC)
-		offset = 0;
-
 	if (offset) {
 		int one_clock;
 
@@ -2405,12 +2402,6 @@ static int esp_slave_configure(struct scsi_device *dev)
 	struct esp_target_data *tp = &esp->target[dev->id];
 	int goal_tags, queue_depth;
 
-	if (esp->flags & ESP_FLAG_DISABLE_SYNC) {
-		/* Bypass async domain validation */
-		dev->ppr  = 0;
-		dev->sdtr = 0;
-	}
-
 	goal_tags = 0;
 
 	if (dev->tagged_supported) {
@@ -2660,7 +2651,10 @@ static void esp_set_offset(struct scsi_target *target, int offset)
 	struct esp *esp = shost_priv(host);
 	struct esp_target_data *tp = &esp->target[target->id];
 
-	tp->nego_goal_offset = offset;
+	if (esp->flags & ESP_FLAG_DISABLE_SYNC)
+		tp->nego_goal_offset = 0;
+	else
+		tp->nego_goal_offset = offset;
 	tp->flags |= ESP_TGT_CHECK_NEGO;
 }