Description of Problem:
From: Chris Pascoe [mailto:c.pascoe@itee.uq.edu.au]
Sent: Tuesday, January 22, 2002 6:58 AM

Hi Alan,

The problem with millions of interrupts being generated by the aacraid
driver on some hardware is caused by reversed arguments to time_before in
rx_sync_cmd.  This causes every synchronous command sent to the controller
to miss acknowledgement, including our one to start the adapter.  When
interrupts are subsequently re-enabled, we get a continuous stream of
interrupts as the command has actually completed, and there is no path in
aac_rx_intr to acknowledge the command.

The following patch corrects the described problem.

--- linux/drivers/scsi/aacraid/rx.c.orig	Tue Jan 22 22:40:58 2002
+++ linux/drivers/scsi/aacraid/rx.c	Tue Jan 22 22:41:19 2002
@@ -199,7 +199,7 @@
 	/*
 	 *	Wait up to 30 seconds
 	 */
-	while (time_before(start+30*HZ, jiffies))
+	while (time_before(jiffies, start+30*HZ))
 	{
 		udelay(5);	/* Delay 5 microseconds to let Mon960 get info. 
*/
 		/*

Regards,
Chris



Version-Release number of selected component (if applicable):
~ 2.4.9-20 kernel, stock kernel 2.4.17 through 2.4.18-pre4 at least.

How Reproducible:
Always on systems with i960 embedded RAID and aacraid driver.

Steps to Reproduce:
1. start aacraid driver
2. 
3. 

Actual Results:
150,000 interrupts/second or more, even with no disk activity.

Expected Results:
a very very small number of interrupts per second

Additional Information: