Subject: [PATCH] ep93xx: Implement double buffering for M2M DMA channels

From: [email-masked] (Rafal Prylowski)
Date: Tue, 17 Apr 2012 09:15:39 +0200

On 2012-04-16 20:59, H Hartley Sweeten wrote:
> On Wednesday, April 11, 2012 12:19 AM, Rafal Prylowski wrote:
> 
> Rafal,
> 
> This patch still doesn't work on my ep93xx system.

<snip>

> It appears your patch is causing an interrupt storm on my system.
> 

Could you please apply the following patch on top of double buffering
patch? I would like to know the state of dma channel when you get
that interrupt storm.

Thanks,
RP

Index: linux-2.6/drivers/dma/ep93xx_dma.c
===================================================================
--- linux-2.6.orig/drivers/dma/ep93xx_dma.c
+++ linux-2.6/drivers/dma/ep93xx_dma.c
@@ -606,6 +606,7 @@ static int m2m_hw_interrupt(struct ep93x
 	 */
 	last = list_first_entry(edmac->active.next,
 		struct ep93xx_dma_desc, node)->txd.cookie;
+	printk("M2M: %x %s\n", status, last ? "last" : "");
 
 	/*
 	 * Use M2M DMA Buffer FSM and Control FSM to check current state of