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

[Andy Shevchenko <andy.shevchenko@xxxxxxxxx>]

On Thu, Apr 14, 2022 at 5:57 AM Mario Limonciello
<mario.limonciello@xxxxxxx> 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.

Good catch, Mario, and thanks for the prompt fix!
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>

> Cc: Shreeya Patel <shreeya.patel@xxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 5467801f1fcb ("gpio: Restrict usage of GPIO chip irq members before initialization")
> Reported-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> Link: https://lore.kernel.org/linux-gpio/BL1PR12MB51577A77F000A008AA694675E2EF9@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/T/#u
> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> ---
>  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;
>  }
>
> --
> 2.34.1
>


-- 
With Best Regards,
Andy Shevchenko