diff -urN ../linux-2.6.19-orig/drivers/ide/ide-disk.c drivers/ide/ide-disk.c
--- ../linux-2.6.19-orig/drivers/ide/ide-disk.c	2006-11-30 06:57:37 +0900
+++ drivers/ide/ide-disk.c	2006-12-05 01:16:07 +0900
@@ -244,6 +244,11 @@
 		cyl   = track / drive->head;
 
 		pr_debug("%s: CHS=%u/%u/%u\n", drive->name, cyl, head, sect);
+		if (cyl > 65535) {
+			printk(KERN_ERR "ide-disk WARNING: %s: cylinder"
+			       " overflow in CHS access (sector %lX,"
+			       " cyl %u)\n", drive->name, block, cyl);
+		}
 
 		hwif->OUTB(0x00, IDE_FEATURE_REG);
 		hwif->OUTB(nsectors.b.low, IDE_NSECTOR_REG);