[i2c] [PATCH] of/i2c: don't pass -1 to irq_dispose_mapping, otherwise kernel will oops

[Grant Likely]

On Sat, Jul 12, 2008 at 2:00 AM, Wolfram Sang <w.sang at pengutronix.de> wrote:
> On Fri, Jul 11, 2008 at 12:23:23PM -0600, Grant Likely wrote:
>> On Fri, Jul 11, 2008 at 09:48:59PM +0400, Anton Vorontsov wrote:
>> > Firstly kernel warns at set_irq_chip, and then dies completely:
>> >
>> > Trying to install chip for IRQ-1
>> >
>> > diff --git a/drivers/of/of_i2c.c b/drivers/of/of_i2c.c
>> > index b2ccdcb..95a24de 100644
>> > --- a/drivers/of/of_i2c.c
>> > +++ b/drivers/of/of_i2c.c
>> > @@ -93,10 +93,8 @@ void of_register_i2c_devices(struct i2c_adapter *adap,
>> >             if (info.irq == NO_IRQ)
>> >                     info.irq = -1;
>>
>> What is the reason that info.irq is set to -1 in the first place?  This
>> looks like another bug to me.  Does something in the i2c layer depend on
>> the -1 value?
>>
>
> You already acked a fix to this :) I wasn't sure if my patch would
> make it on its own, as Jon Smirl was also working on fixes to of_i2c.c
> and he seemed to pick up this issue, too.

Ugh, I have trouble remembering what I've done from one day to the next.  :-/

After looking at it again, I'm inclined to prefer the NO_IRQ fix.
There is a smaller user base of of_i2c and so it will have a much
smaller impact if it breaks stuff.  It also has the added advantage of
encouraging people to actually fix the drivers that assume -1.

Cheers,
g.

-- 
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.