[PATCH] IDE cable detection on Apple PowerBook

[TOMARI Hisanobu <posco.grubb@gmail.com>]

This patch against 2.6.28.8 modifies the behavior of 80c cable detection 
of drivers/ide/pmac.c.
As IDE cable used on Apple PowerBook/iBook laptops are always of "Short 40" 
type when the firmware says it's 80 conductor one, the cable detection should 
return ATA_CBL_PATA40_SHORT on those machines.
This enables to automatically use UDMA5 even with drives that doesn't correctly 
detect those cables on Apple laptops.

Signed-off-by: TOMARI Hisanobu <posco.grubb@gmail.com>

--- linux-2.6.28.8/drivers/ide/pmac.c.orig	2009-03-21 23:07:19.177956922 +0900
+++ linux-2.6.28.8/drivers/ide/pmac.c	2009-03-22 09:57:58.774048828 +0900
@@ -917,10 +917,19 @@ static u8 pmac_ide_cable_detect(ide_hwif
 		(pmac_ide_hwif_t *)dev_get_drvdata(hwif->gendev.parent);
 	struct device_node *np = pmif->node;
 	const char *cable = of_get_property(np, "cable-type", NULL);
+	struct device_node *root = of_find_node_by_path("/");
+	const char *model = of_get_property(root, "model", NULL);
 
 	/* Get cable type from device-tree. */
 	if (cable && !strncmp(cable, "80-", 3))
+	  {
+	    /* Some drives fail to detect 80c cable in PowerBook */
+	    /* These machine use proprietary short IDE cable anyway */
+	    if (!strncmp(model,"PowerBook", 9))
+		return ATA_CBL_PATA40_SHORT;
+	    else
 		return ATA_CBL_PATA80;
+	  }
 
 	/*
 	 * G5's seem to have incorrect cable type in device-tree.