Re: [PATCH 2/2] i2c: i2c-omap: Call request_irq with IRQF_DISABLED

[Paul Walmsley <paul@pwsan.com>]

On Thu, 12 Mar 2009, Kauppi Ari (EXT-Ixonos/Oulu) wrote:

> My process was:
> 
> 1) Take 2.6.28-based kernel on custom OMAP3430ES3.0 hardware with
> CONFIG_DEBUG_LOCKDEP enabled. There are no spurious interrupts and
> everything works.
> 
> 2) Disable CONFIG_DEBUG_LOCKDEP and all other kernel debugging options.
> Spurious interrupts start to appear on several IRQs, especially with IRQ
> 56 (I2C1).
> 
> 3) Apply Richard's patch. All spurious interrupts for IRQ 56 are gone
> but frequency of others increase.
> 
> 4) Set IRQF_DISABLED in i2c-omap and the frequency of other spurious
> interrupts decreases considerably. However, I'm starting to realize that
> the real problem is probably elsewhere.
> 
> My test setup is pretty systematic, it does not have any user
> interaction in it. I have a relay controlling the power to the device
> and have taken logs of about 12000 boots with different kernel options
> and patches applied.

Thanks for the details.  Can you extract the list of spurious IRQ warnings 
that you're getting, and post them?  I suspect that, like I2C, many of the 
driver ISRs are not reading back the device interrupt status registers 
after they clear them.


- Paul