[PATCH] fix the interrupt loss problem on powerpc IPIC (2.6.23)

[dayu at datangmobile.cn]

From: Da Yu <dayu at datangmobile.cn>
Date: Tue, 17 Feb 2009 19:58:20 +0800
Subject: [PATCH] fix the interrupt loss problem on powerpc IPIC (2.6.23)

Signed-off-by: Da Yu <dayu at datangmobile.cn>
---

--- a/arch/powerpc/sysdev/ipic.c	2009-02-17 15:10:18.000000000 +0800
+++ b/arch/powerpc/sysdev/ipic.c	2009-02-17 20:05:28.000000000 +0800
@@ -561,8 +561,7 @@ static void ipic_ack_irq(unsigned int vi

 	spin_lock_irqsave(&ipic_lock, flags);

-	temp = ipic_read(ipic->regs, ipic_info[src].pend);
-	temp |= (1 << (31 - ipic_info[src].bit));
+	temp = 1 << (31 - ipic_info[src].bit);
 	ipic_write(ipic->regs, ipic_info[src].pend, temp);

 	spin_unlock_irqrestore(&ipic_lock, flags);
@@ -581,8 +580,7 @@ static void ipic_mask_irq_and_ack(unsign
 	temp &= ~(1 << (31 - ipic_info[src].bit));
 	ipic_write(ipic->regs, ipic_info[src].mask, temp);

-	temp = ipic_read(ipic->regs, ipic_info[src].pend);
-	temp |= (1 << (31 - ipic_info[src].bit));
+	temp = 1 << (31 - ipic_info[src].bit);
 	ipic_write(ipic->regs, ipic_info[src].pend, temp);

 	spin_unlock_irqrestore(&ipic_lock, flags);






 

-----邮件原件-----
发件人: Li Yang-R58472 [mailto:LeoLi at freescale.com] 
发送时间: 2009年2月17日 18:17
收件人: 笪禹; linux-kernel at vger.kernel.org
抄送: linuxppc-dev at ozlabs.org
主题: RE: PROBLEM: incorrect interrupt ack lead to interrupt loss on freescale powerpc

> -----Original Message-----
> From: dayu at datangmobile.cn [mailto:dayu at datangmobile.cn]
> Sent: Tuesday, February 17, 2009 4:34 PM
> To: linux-kernel at vger.kernel.org
> Cc: Li Yang-R58472
> Subject: PROBLEM: incorrect interrupt ack lead to interrupt loss on 
> freescale powerpc
> 
>  
> [1.] One line summary of the problem: incorrect interrupt ack  lead to 
> interrupt loss

Acked-by: Li Yang <leoli at freescale.com>

However, please resend the patch with a brief description and Signed-off-by at the top of the patch.  You can read the Documentation/SubmittiongPatches for more information, or even a Chinese version under Documentation/zh_CN/.

Here are some small comments about the patch itself,

--- a/arch/powerpc/sysdev/ipic.c	2009-02-17 15:10:18.000000000 +0800
+++ b/arch/powerpc/sysdev/ipic.c	2009-02-17 15:10:24.000000000 +0800
@@ -9,6 +9,7 @@
  * under  the terms of  the GNU General  Public License as published by the
  * Free Software Foundation;  either version 2 of the  License, or (at your
  * option) any later version.
+ * Da Yu <dayu at datangmobile.cn> fixed the interrupt loss problem on 
+ powerpc IPIC


It's not recommended to add changelog in the source now.  Please describe in the patch description area.

  */
 #include <linux/kernel.h>
 #include <linux/init.h>
@@ -561,8 +562,7 @@
 
 	spin_lock_irqsave(&ipic_lock, flags);
 
-	temp = ipic_read(ipic->regs, ipic_info[src].pend);
-	temp |= (1 << (31 - ipic_info[src].bit));
+	temp = (1 << (31 - ipic_info[src].bit));


Remove unneeded brackets.


 	ipic_write(ipic->regs, ipic_info[src].pend, temp);
 
 	spin_unlock_irqrestore(&ipic_lock, flags); @@ -581,8 +581,7 @@
 	temp &= ~(1 << (31 - ipic_info[src].bit));
 	ipic_write(ipic->regs, ipic_info[src].mask, temp);
 
-	temp = ipic_read(ipic->regs, ipic_info[src].pend);
-	temp |= (1 << (31 - ipic_info[src].bit));
+	temp = (1 << (31 - ipic_info[src].bit));

Same as above.


 	ipic_write(ipic->regs, ipic_info[src].pend, temp);
 
 	spin_unlock_irqrestore(&ipic_lock, flags);