Re: Regression in 32-bit ppc kernel

[Larry Finger]

On 04/27/2012 05:26 PM, Benjamin Herrenschmidt wrote:
> On Fri, 2012-04-27 at 10:38 -0500, Larry Finger wrote:
>
> > Sorry, I was unable to find anything in debugfs to help me learn about interrupt
> > mapping. The value of CONFIG_NR_IRQS is already 512. I have not tried reducing
> > it to 128. The setting for CONFIG_SPARSE_IRQ was on, and changing it to off did
> > not make any difference.
> >
> > I finished the bisection, which led to
> >
> > commit a79dd5ae5a8f49688d65b89a859f2b98a7ee5538
> > Author: Benjamin Herrenschmidt<benh@xxxxxxxxxxxxxxxxxxx>
> > Date:   Thu Dec 15 11:13:03 2011 +1100
> >
> >       tty/serial/pmac_zilog: Fix suspend&  resume
> >
> > As this seemed to be an improbable result, I did the full test by checking out
> > the previous commit (43ca5d3). That resulted in a "good" result. Then I used
> > quilt to add commit a79dd5a as a patch and the fault returned. I then noticed
> > that you said in the commit message that "I removed some code for handling
> > unexpected interrupt which should never be hit...". It appears that my box does
> > indeed hit such an unexpected interrupt.
> >
> > I could always get rid of the fault by disabling CONFIG_SERIAL_PMACZILOG, but I
> > would like to fix the problem if possible.
>
> Right, it should be fixed. I need to understand where the unexpected
> interrupt comes from. Can you tell me (or remind me) what specific
> machine model you are using ? Are you putting the console on the serial
> port ?

It is a 15" Powerbook G4. I think they call it a Titanium. The console is not on 
a serial port. In fact, the reason that I did not think this patch was a problem 
is because the serial port does not appear to be connected to an external port. 
I was unaware that there was a serial port on the motherboard. There is a modem 
jack, but no 9 or 25-pin connectors that would indicate a standard serial port.

There are two stack dumps with the same trace. I posted the first, but the 
second is preceded by the lines

[<c02adca0] pmz_interrupt
Disabling IRQ #23
ttyPZ1: IrDA setup for 57600 bps, dongle version: 4
ttyPZ1: IrDA setup for 115200 bps, dongle version: 4
irq23: nobody cared (try booting with the "irqpoll" option

As I am not sure how to put options in with yaboot, I have not tried that.

Larry


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/