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

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

[dayu]

From: Da Yu <dayu@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@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@freescale.com] 
发送时间: 2009年2月17日 18:17
收件人: 笪禹; linux-kernel@vger.kernel.org
抄送: linuxppc-dev@ozlabs.org
主题: RE: PROBLEM: incorrect interrupt ack lead to interrupt loss on freescale powerpc

> -----Original Message-----
> From: dayu@datangmobile.cn [mailto:dayu@datangmobile.cn]
> Sent: Tuesday, February 17, 2009 4:34 PM
> To: linux-kernel@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@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@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);

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

[Kumar Gala]

On Feb 17, 2009, at 6:44 AM, <dayu@datangmobile.cn> <dayu@datangmobile.cn 
 > wrote:

> From: Da Yu <dayu@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@datangmobile.cn>
> ---

Please provide a bit more description as to why this fixes the issue.

- k

>
>
> --- 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);

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

[Josh Boyer]

On Tue, Feb 17, 2009 at 08:12:33AM -0600, Kumar Gala wrote:
>
> On Feb 17, 2009, at 6:44 AM, <dayu@datangmobile.cn> <dayu@datangmobile.cn 
> > wrote:
>
>> From: Da Yu <dayu@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@datangmobile.cn>
>> ---
>
> Please provide a bit more description as to why this fixes the issue.

Including whether it still applies to mainline, since your topic seems
to indicate it's for 2.6.23.  That is pretty old by now.

josh

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

[Li Yang]

On Tue, Feb 17, 2009 at 10:12 PM, Kumar Gala <galak@kernel.crashing.org> wrote:
>
> On Feb 17, 2009, at 6:44 AM, <dayu@datangmobile.cn> <dayu@datangmobile.cn>
> wrote:
>
>> From: Da Yu <dayu@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@datangmobile.cn>
>> ---
>
> Please provide a bit more description as to why this fixes the issue.

The pending register is write 1 clear.  If there are more than one
external interrupts pending at the same time, acking the first
interrupt will also clear other interrupt pending bits.  That will
cause loss of interrupt.

- Leo

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

[Kumar Gala]

On Feb 17, 2009, at 8:38 AM, Li Yang wrote:

> On Tue, Feb 17, 2009 at 10:12 PM, Kumar Gala <galak@kernel.crashing.org 
> > wrote:
>>
>> On Feb 17, 2009, at 6:44 AM, <dayu@datangmobile.cn> <dayu@datangmobile.cn 
>> >
>> wrote:
>>
>>> From: Da Yu <dayu@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@datangmobile.cn>
>>> ---
>>
>> Please provide a bit more description as to why this fixes the issue.
>
> The pending register is write 1 clear.  If there are more than one
> external interrupts pending at the same time, acking the first
> interrupt will also clear other interrupt pending bits.  That will
> cause loss of interrupt.
>
> - Leo

Thanks.  That should be included in the commit message.

- k

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

[Li Yang]

On Tue, Feb 17, 2009 at 10:32 PM, Josh Boyer <jwboyer@linux.vnet.ibm.com> wrote:
> On Tue, Feb 17, 2009 at 08:12:33AM -0600, Kumar Gala wrote:
>>
>> On Feb 17, 2009, at 6:44 AM, <dayu@datangmobile.cn> <dayu@datangmobile.cn
>> > wrote:
>>
>>> From: Da Yu <dayu@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@datangmobile.cn>
>>> ---
>>
>> Please provide a bit more description as to why this fixes the issue.
>
> Including whether it still applies to mainline, since your topic seems
> to indicate it's for 2.6.23.  That is pretty old by now.

The problem still exists in mainline.  But the patch doesn't seem to apply.

Dayu,

Could you re-spin the patch for the latest kernel?  Thanks.

- Leo