Re: [PATCH v2 1/1] gpio: Request interrupts after IRQ is initialized

["Limonciello, Mario" <mario.limonciello@amd.com>]

On 4/22/2022 08:14, 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@collabora.com>
> Cc: stable@vger.kernel.org
> Fixes: 5467801f1fcb ("gpio: Restrict usage of GPIO chip irq members before initialization")
> Reported-by: Mario Limonciello <mario.limonciello@amd.com>
> Link: https://lore.kernel.org/linux-gpio/BL1PR12MB51577A77F000A008AA694675E2EF9@BL1PR12MB5157.namprd12.prod.outlook.com/T/#u
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
> Reviewed-by: Shreeya Patel <shreeya.patel@collabora.com>
> Tested-By: Samuel Čavoj <samuel@cavoj.net>
> Tested-By: lukeluk498@gmail.com Link:
> Link: https://gitlab.freedesktop.org/drm/amd/-/issues/1979
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=215850
> Link: https://gitlab.freedesktop.org/drm/amd/-/issues/1976
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Acked-by: Linus Walleij <linus.walleij@linaro.org>

Takashi hit this as well recently and provided a few more tags.

BugLink: https://bugzilla.suse.com/show_bug.cgi?id=1198697
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Takashi Iwai <tiwai@suse.de>


> ---
> v1->v2:
>   * Pick up acked-by/reviewed-by/link/tested-by
> 
>   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;
>   }
>