linux-kernel - Re: [PATCH RESEND v2] gpio: omap: Add omap_gpio_disable/enable

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Message-ID: <e54b0558-80ca-4352-b54a-22f9eb8c9001@ti.com>
Date: Fri, 8 Nov 2024 09:43:05 -0600
From: Judith Mendez <jm@...com>
To: Bartosz Golaszewski <brgl@...ev.pl>, <linux-gpio@...r.kernel.org>
CC: Linus Walleij <linus.walleij@...aro.org>,
        Santosh Shilimkar
	<ssantosh@...nel.org>,
        <linux-kernel@...r.kernel.org>, Kevin Hilman
	<khilman@...nel.org>,
        Bin Liu <b-liu@...com>, <linux-omap@...r.kernel.org>
Subject: Re: [PATCH RESEND v2] gpio: omap: Add omap_gpio_disable/enable_irq
 calls

Hi Bartosz,

On 11/6/24 7:42 AM, Bartosz Golaszewski wrote:
> On Tue, Nov 5, 2024 at 8:00 PM Bin Liu <b-liu@...com> wrote:
>>
>> On Tue, Nov 05, 2024 at 12:47:58PM -0600, Judith Mendez wrote:
>>> Hi Kevin,
>>>
>>> On 11/1/24 9:29 AM, Kevin Hilman wrote:
>>>> Hi Judith,
>>>>
>>>> Judith Mendez <jm@...com> writes:
>>>>
>>>>> From: Bin Liu <b-liu@...com>
>>>>>
>>>>> Add omap_gpio_disable_irq and omap_gpio_enable_irq
>>>>> calls in gpio-omap.
>>>>>
>>>>> Currently, kernel cannot disable gpio interrupts in
>>>>> case of a irq storm, so add omap_gpio_disable/enable_irq
>>>>> so that interrupts can be disabled/enabled.
>>>>>
>>>>> Signed-off-by: Bin Liu <b-liu@...com>
>>>>> [Judith: Add commit message]
>>>>> Signed-off-by: Judith Mendez <jm@...com>
>>>>
>>>> Thanks for this patch.  Can you give a bit more context on the
>>>> problem(s) this solves and on which SoCs/platforms it was
>>>> developed/validated?
>>>
>>> Sorry for the late response. Patch was tested/developed on am335x
>>> device BBB, If you feed a PWM signal at 200KHz frequency to
>>> GPIO, and execute gpiomon 0 12 &, Linux will be unresponsive
>>> even after CTRL+C without these 2 functions in this patch. Once
>>> this patch is applied, you can get console back after hitting
>>> CTRL+C and then proceed to kill gpiomon.
>>
>> In addtion to Judith's explanation, when the PWM is applied to a GPIO
>> pin, kernel detects the interrupt storm and disables the irq, however,
>> without these callbacks, this gpio platform driver doesn't really
>> disable the interrupt in the gpio controller, so the interrupt storm is
>> still happening and handled by this gpio controller driver then causes
>> Linux unresponsive.
>>
>> -Bin.
> 
> I take it that this is a fix then and should have relevant Fixes and Cc tags?

ok, will send v3 with fixes tag.

~ Judith