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From: Linus Walleij <linus.walleij@linaro.org>
To: Stephen Warren <swarren@wwwdotorg.org>,
	Grant Likely <grant.likely@secretlab.ca>,
	Rob Herring <rob.herring@calxeda.com>
Cc: Linus Walleij <linus.walleij@stericsson.com>,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Stephen Warren <swarren@nvidia.com>,
	Anmar Oueja <anmar.oueja@linaro.org>,
	Lee Jones <lee.jones@linaro.org>
Subject: Re: [PATCH] pinctrl/nomadik: use irq_create_mapping()
Date: Tue, 23 Oct 2012 10:31:45 +0200	[thread overview]
Message-ID: <CACRpkdZLgnEHAKiyZBT1FTQPdp69rTOQ9ba9ZQ0y4eLODw4zeA@mail.gmail.com> (raw)
In-Reply-To: <5085A7CA.3070001@wwwdotorg.org>

On Mon, Oct 22, 2012 at 10:08 PM, Stephen Warren <swarren@wwwdotorg.org> wrote:
> On 10/22/2012 02:14 AM, Linus Walleij wrote:

>> It's an IRQ handler so it should be robust to spurious IRQs due to
>> transient hardware states etc I believe.
>>
>> So if there is a transient IRQ before gpio_to_irq() is called -> boom.
>
> I wonder though (a) why it would be unmasked in HW, and (b) why the
> software would even look at the status bit if no handler were registered?

That's true of course ... OK I'll update the patch.

Still I'm not feeling good about the irq_create_mapping/irq_find_mapping
separation, I think a lot of drivers just get this wrong and it's causing
bugs... it'd be way better if there was just one of them and we could
count on descriptors being allocated after adding any kind of irqdomain
but I have no clue how hard it would be to achieve this.

Yours,
Linus Walleij

WARNING: multiple messages have this Message-ID (diff)
From: linus.walleij@linaro.org (Linus Walleij)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] pinctrl/nomadik: use irq_create_mapping()
Date: Tue, 23 Oct 2012 10:31:45 +0200	[thread overview]
Message-ID: <CACRpkdZLgnEHAKiyZBT1FTQPdp69rTOQ9ba9ZQ0y4eLODw4zeA@mail.gmail.com> (raw)
In-Reply-To: <5085A7CA.3070001@wwwdotorg.org>

On Mon, Oct 22, 2012 at 10:08 PM, Stephen Warren <swarren@wwwdotorg.org> wrote:
> On 10/22/2012 02:14 AM, Linus Walleij wrote:

>> It's an IRQ handler so it should be robust to spurious IRQs due to
>> transient hardware states etc I believe.
>>
>> So if there is a transient IRQ before gpio_to_irq() is called -> boom.
>
> I wonder though (a) why it would be unmasked in HW, and (b) why the
> software would even look at the status bit if no handler were registered?

That's true of course ... OK I'll update the patch.

Still I'm not feeling good about the irq_create_mapping/irq_find_mapping
separation, I think a lot of drivers just get this wrong and it's causing
bugs... it'd be way better if there was just one of them and we could
count on descriptors being allocated after adding any kind of irqdomain
but I have no clue how hard it would be to achieve this.

Yours,
Linus Walleij

  reply	other threads:[~2012-10-23  8:31 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-19 15:09 [PATCH] pinctrl/nomadik: use irq_create_mapping() Linus Walleij
2012-10-19 15:09 ` Linus Walleij
2012-10-19 16:22 ` Stephen Warren
2012-10-19 16:22   ` Stephen Warren
2012-10-22  8:14   ` Linus Walleij
2012-10-22  8:14     ` Linus Walleij
2012-10-22 20:08     ` Stephen Warren
2012-10-22 20:08       ` Stephen Warren
2012-10-23  8:31       ` Linus Walleij [this message]
2012-10-23  8:31         ` Linus Walleij

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