440GX interrupt

[Eugene Surovegin]

On Thu, Feb 17, 2005 at 02:54:14PM -0800, Eugene Surovegin wrote:
> Probably it's a race which cannot be avoided anyway because external 
> IRQs are completely async, and your version of ppc4xx_pic.c just has a 
> bug. I'll think about it a little more.

Uhh, yes, I think it's a bug in 4xx version of disable_irq.

We have to ACK parent UIC after disabling IRQ to prevent false 
triggering in case this IRQ was already pending during disable_irq 
call.

Here is a patch against current 2.6, so you can get an idea what I'm 
talking about :):

===== arch/ppc/syslib/ppc4xx_pic.c 1.13 vs edited =====
--- 1.13/arch/ppc/syslib/ppc4xx_pic.c	2005-01-03 15:49:19 -08:00
+++ edited/arch/ppc/syslib/ppc4xx_pic.c	2005-02-17 15:31:07 -08:00
@@ -48,6 +48,7 @@
 {									\
 	ppc_cached_irq_mask[n] &= ~IRQ_MASK_UIC##n(irq);		\
 	mtdcr(DCRN_UIC_ER(UIC##n), ppc_cached_irq_mask[n]);		\
+	ACK_UIC##n##_PARENT						\
 }									\
 									\
 static void ppc4xx_uic##n##_ack(unsigned int irq)			\


You can send me your version of ppc4xx_pic.c or put it somewhere on 
www and I'll make a patch for it.

--
Eugene