On 05/29/2012 09:20 AM, Mitchell Tasman wrote:
> Gilles,
>
> On 05/25/2012 08:20 AM, Gilles Chanteperdrix wrote:
>> On 05/25/2012 11:18 AM, Mitchell Tasman wrote:
>
>>> Thank you once again for your excellent support, and I very much look
>>> forward to the updated I-Pipe for ARM 2.6.38.8 patch set.
>>
>> You are welcome. The patch should be done during the week-end.
>
> Hi. I noticed that you made some commits on the for-ipipe-2.6.38-arm
> branch of your ipipe-gch.git repository, and decided to take a quick
> look, leading to a question.
>
> In arch/arm/plat-omap/gpio.c, I found that you reverted-out some changes
> relating to earlier fixes to handling of GPIO interrupts, bringing the
> source closer to the vanilla linux 2.6.38.8 version.
>
> One change that had been made along the way on the for-ipipe-2.6.38-arm
> branch was to add a gpio_mask_ack_irq() function, and invoke it like so
> from gpio_irq_handler(), instead of invoking gpio_ack_irq():
>
> #ifndef CONFIG_IPIPE
> desc->irq_data.chip->irq_ack(&desc->irq_data);
> #else /* CONFIG_IPIPE */
> desc->irq_data.chip->irq_mask_ack(&desc->irq_data);
> #endif /* CONFIG_IPIPE */
>
> With the latest commits, the gpio_mask_ack_irq() function remains, but
> it is no longer invoked, with gpio_ack_irq() being called
> unconditionally instead, as with the vanilla 2.6.38.8 source.
desc->irq_data.chip->irq_mask_ack is the "mask_ack" method of the parent
irq, not gpio_mask_ack_irq. gpio_mask_ack_irq is called normally when
acknowledging the gpio irq.
>
> Looking at I-Pipe support for 3.0.13, I found that the inline function
> chained_irq_enter() is called at the equivalent place in
> gpio_irq_handler(), and that function appears to invoke
> gpio_mask_ack_irq() when available (which it is for OMAP in your tree),
> and otherwise calls gpio_ack_irq().
>
> I just wanted to double-check with you that the vanilla 2.6.38.8 source
> is indeed correct (or at least harmless) in its unconditional calling of
> gpio_ack_irq() from gpio_irq_handler(), and that the apparent difference
> in behavior between the 3.0.13 and 2.6.38.8 I-Pipe patch sets is fine as
> well.
Everything happens with irqs off, so masking is not strictly necessary I
guess.
--
Gilles.
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