RE: ppc826x BAD interrupts

[Jeff Angielski <jeff@theptrgroup.com>]

Nice catch.  Adding the sync does, in fact, fix the problem.

I guess this means I need to go back to Google-school since I scoured
the net looking for this very information...  ;)

Jeff Angielski
The PTR Group


On Fri, 2004-01-16 at 11:29, Muhammad Sarwar wrote:
> This problem was discussed on mailing list before also and you can eliminate this problem by inserting a sync instruction at a certain place in the 8260 interrupt handling code. See, for example, http://www.geocrawler.com/archives/3/8358/2002/11/100/10173445/
>
> Add a __asm__ volatile("sync"); at the end of the m8260_mask_and_ack  function in arch/ppc/kernel/ppc8260_pic.c to fix it.
>
>
> Regards,
>
> Muhammad Sarwar
> Mangrove Systems Inc.
>
>
> -----Original Message-----
> From: Jeff Angielski [mailto:jeff@theptrgroup.com]
> Sent: Friday, January 16, 2004 11:03 AM
> To: linuxppc-dev@lists.linuxppc.org
> Subject: ppc826x BAD interrupts
>
>
> Looking at /proc/interrupts, I see a large number of "BAD" interrups on
> both my MPC8260 reference board (2.4.21) and my PPC8266 custom board
> (2.4.23).  Both use u-boot as the bootloader.
>
> bash-2.05# cat /proc/interrupts
>            CPU0
>  24:          0   8260 SIU   Edge      PCI IRQ demux
>  33: 2658326944   8260 SIU   Edge      fenet
>  40:      32524   8260 SIU   Edge      uart
>  41:          0   8260 SIU   Edge      uart
> BAD:    8862006  <<====== this the problem
>
> The source of this count is ppc_spurious_interrupts which is incremented
> in the arch/ppc/kernel/irq.c if:
>
> 	1) there is no interrupt handler installed
>
> 	2) SIVEC is showing zero (no interrupts pending)
>
> Looking into the problem it would appear that the problem is the later
> case and the get_irq() function in ppc8260_pic.c is indeed reading a
> zero from the SIVEC.
>
> The questions I have are:
>
> 1) Has anybody seen this behavior on their PowerPC platform?
> 2) Does anybody know why the SIVEC would be showing a zero?
>
> TIA,
> Jeff Angielski
> The PTR Group
>
>


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