linux-kernel - Re: [PATCH] gpio: Request interrupts after IRQ is initialized

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Date:   Tue, 19 Apr 2022 11:40:53 +0200
From:   Samuel Čavoj <samuel@...oj.net>
To:     Mario Limonciello <mario.limonciello@....com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Shreeya Patel <shreeya.patel@...labora.com>,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        Basavaraj.Natikar@....com, Richard.Gong@....com,
        stable@...r.kernel.org
Subject: Re: [PATCH] gpio: Request interrupts after IRQ is initialized

Thanks,

this fixes the issue on an ASUS UM325 laptop.

On 2022-04-14 04:57, Mario Limonciello wrote:
> commit 5467801f1fcb ("gpio: Restrict usage of GPIO chip irq members 
> before
> initialization") attempted to fix a race condition that lead to a NULL
> pointer, but in the process caused a regression for _AEI/_EVT declared
> GPIOs. This manifests in messages showing deferred probing while trying
> to allocate IRQs like so:
> 
> [    0.688318] amd_gpio AMDI0030:00: Failed to translate GPIO pin
> 0x0000 to IRQ, err -517
> [    0.688337] amd_gpio AMDI0030:00: Failed to translate GPIO pin
> 0x002C to IRQ, err -517
> [    0.688348] amd_gpio AMDI0030:00: Failed to translate GPIO pin
> 0x003D to IRQ, err -517
> [    0.688359] amd_gpio AMDI0030:00: Failed to translate GPIO pin
> 0x003E to IRQ, err -517
> [    0.688369] amd_gpio AMDI0030:00: Failed to translate GPIO pin
> 0x003A to IRQ, err -517
> [    0.688379] amd_gpio AMDI0030:00: Failed to translate GPIO pin
> 0x003B to IRQ, err -517
> [    0.688389] amd_gpio AMDI0030:00: Failed to translate GPIO pin
> 0x0002 to IRQ, err -517
> [    0.688399] amd_gpio AMDI0030:00: Failed to translate GPIO pin
> 0x0011 to IRQ, err -517
> [    0.688410] amd_gpio AMDI0030:00: Failed to translate GPIO pin
> 0x0012 to IRQ, err -517
> [    0.688420] amd_gpio AMDI0030:00: Failed to translate GPIO pin
> 0x0007 to IRQ, err -517
> 
> The code for walking _AEI doesn't handle deferred probing and so this 
> leads
> to non-functional GPIO interrupts.
> 
> Fix this issue by moving the call to `acpi_gpiochip_request_interrupts` 
> to
> occur after gc->irc.initialized is set.
> 
> Cc: Shreeya Patel <shreeya.patel@...labora.com>
> Cc: stable@...r.kernel.org
> Fixes: 5467801f1fcb ("gpio: Restrict usage of GPIO chip irq members
> before initialization")
> Reported-by: Mario Limonciello <mario.limonciello@....com>
> Link:
> https://lore.kernel.org/linux-gpio/BL1PR12MB51577A77F000A008AA694675E2EF9@BL1PR12MB5157.namprd12.prod.outlook.com/T/#u
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>

Tested-By: Samuel Čavoj <samuel@...oj.net>

> ---
>  drivers/gpio/gpiolib.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index 085348e08986..b7694171655c 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -1601,8 +1601,6 @@ static int gpiochip_add_irqchip(struct gpio_chip 
> *gc,
> 
>  	gpiochip_set_irq_hooks(gc);
> 
> -	acpi_gpiochip_request_interrupts(gc);
> -
>  	/*
>  	 * Using barrier() here to prevent compiler from reordering
>  	 * gc->irq.initialized before initialization of above
> @@ -1612,6 +1610,8 @@ static int gpiochip_add_irqchip(struct gpio_chip 
> *gc,
> 
>  	gc->irq.initialized = true;
> 
> +	acpi_gpiochip_request_interrupts(gc);
> +
>  	return 0;
>  }

Sam