cciss updates for 2.6 [5 of 11]

[mikem]

Patch 5 of 11. Please apply in order.
This patch addresses a bug in the ASIC on the 6400 series controllers. When
prefetching from host memory we grab an extra 750 or so bytes of data. If
this occurs on a memory boundary the machine will MCA. This bug affects
IPF and Alpha based platforms. It is not known to be a problem on x86.
Prefetch will be disabled via the f/w. We need to enable it on x86 to
address a _big_ performance hit on RAID 1 operations.
It is in the 2.4 tree.
--------------------------------------------------------------------------------------
diff -burN lx261-p004/drivers/block/cciss.c lx261/drivers/block/cciss.c
--- lx261-p004/drivers/block/cciss.c	2004-01-21 17:02:06.000000000 -0600
+++ lx261/drivers/block/cciss.c	2004-01-22 14:12:04.000000000 -0600
@@ -2277,6 +2277,17 @@
 		printk("Does not appear to be a valid CISS config table\n");
 		return -1;
 	}
+
+#ifdef CONFIG_X86
+{
+	/* Need to enable prefetch in the SCSI core for 6400 in x86 */
+	__u32 prefetch;
+	prefetch = readl(&(c->cfgtable->SCSI_Prefetch));
+	prefetch |= 0x100;
+	writel(prefetch, &(c->cfgtable->SCSI_Prefetch));
+}
+#endif
+
 #ifdef CCISS_DEBUG
 	printk("Trying to put board into Simple mode\n");
 #endif /* CCISS_DEBUG */
diff -burN lx261-p004/drivers/block/cciss_cmd.h lx261/drivers/block/cciss_cmd.h
--- lx261-p004/drivers/block/cciss_cmd.h	2004-01-09 00:59:10.000000000 -0600
+++ lx261/drivers/block/cciss_cmd.h	2004-01-21 17:24:59.000000000 -0600
@@ -265,6 +265,7 @@
   DWORD            Reserved;
   BYTE             ServerName[16];
   DWORD            HeartBeat;
+  DWORD            SCSI_Prefetch;
 } CfgTable_struct;
 #pragma pack()
 #endif // CCISS_CMD_H

Thanks,
mikem
mike.miller@xxxxxx

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