[PATCH] gpio: dwapb: Add robust error handling in interrupt handler

[PATCH] gpio: dwapb: Add robust error handling in interrupt handler

[Liang Hao]

The current interrupt handler silently continues if an interrupt
handling fails, which may lead to interrupt storms. Add proper
error handling to gracefully recover from failed interrupt
handling.

When generic_handle_irq() fails, the following recovery actions are
taken:
  - Write EOI to clear the pending interrupt
  - Mask the interrupt to prevent immediate re-triggering
  - Disable the interrupt to stop further interrupts on this line

These measures prevent the system from being overwhelmed by repeated
unhandled interrupts while logging a rate-limited warning for
debugging purposes.

Signed-off-by: Liang Hao <haohlliang@gmail.com>
---
 drivers/gpio/gpio-dwapb.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpio-dwapb.c b/drivers/gpio/gpio-dwapb.c
index 7b92b233fafe..dec700e3cfb0 100644
--- a/drivers/gpio/gpio-dwapb.c
+++ b/drivers/gpio/gpio-dwapb.c
@@ -209,8 +209,20 @@ static u32 dwapb_do_irq(struct dwapb_gpio *gpio)
 	for_each_set_bit(hwirq, &irq_status, DWAPB_MAX_GPIOS) {
 		int gpio_irq = irq_find_mapping(gen_gc->gc.irq.domain, hwirq);
 		u32 irq_type = irq_get_trigger_type(gpio_irq);
-
-		generic_handle_irq(gpio_irq);
+		int ret;
+		u32 val_intmask, val_inten;
+
+		ret = generic_handle_irq(gpio_irq);
+		if (ret) {
+			dev_warn_ratelimited(gpio->dev, "Failed to handle irq %d\n", gpio_irq);
+			/* Clear the interrupt */
+			dwapb_write(gpio, GPIO_PORTA_EOI, BIT(hwirq));
+			val_intmask = dwapb_read(gpio, GPIO_INTMASK);
+			dwapb_write(gpio, GPIO_INTMASK, val_intmask | BIT(hwirq));
+			val_inten = dwapb_read(gpio, GPIO_INTEN);
+			dwapb_write(gpio, GPIO_INTEN, val_inten & ~BIT(hwirq));
+			continue;
+		}
 
 		if ((irq_type & IRQ_TYPE_SENSE_MASK) == IRQ_TYPE_EDGE_BOTH)
 			dwapb_toggle_trigger(gpio, hwirq);
-- 
2.50.1 (Apple Git-155)

Re: [PATCH] gpio: dwapb: Add robust error handling in interrupt handler

[Linus Walleij]

Hi Liang,

thanks for your patch!

Top posting so tglx get the context...

On Fri, Jul 3, 2026 at 3:49 PM Liang Hao <haohlliang@gmail.com> wrote:

> The current interrupt handler silently continues if an interrupt
> handling fails, which may lead to interrupt storms. Add proper
> error handling to gracefully recover from failed interrupt
> handling.
>
> When generic_handle_irq() fails, the following recovery actions are
> taken:
>   - Write EOI to clear the pending interrupt
>   - Mask the interrupt to prevent immediate re-triggering
>   - Disable the interrupt to stop further interrupts on this line
>
> These measures prevent the system from being overwhelmed by repeated
> unhandled interrupts while logging a rate-limited warning for
> debugging purposes.
>
> Signed-off-by: Liang Hao <haohlliang@gmail.com>
> ---
>  drivers/gpio/gpio-dwapb.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpio/gpio-dwapb.c b/drivers/gpio/gpio-dwapb.c
> index 7b92b233fafe..dec700e3cfb0 100644
> --- a/drivers/gpio/gpio-dwapb.c
> +++ b/drivers/gpio/gpio-dwapb.c
> @@ -209,8 +209,20 @@ static u32 dwapb_do_irq(struct dwapb_gpio *gpio)
>         for_each_set_bit(hwirq, &irq_status, DWAPB_MAX_GPIOS) {
>                 int gpio_irq = irq_find_mapping(gen_gc->gc.irq.domain, hwirq);
>                 u32 irq_type = irq_get_trigger_type(gpio_irq);
> -
> -               generic_handle_irq(gpio_irq);
> +               int ret;
> +               u32 val_intmask, val_inten;
> +
> +               ret = generic_handle_irq(gpio_irq);
> +               if (ret) {
> +                       dev_warn_ratelimited(gpio->dev, "Failed to handle irq %d\n", gpio_irq);
> +                       /* Clear the interrupt */
> +                       dwapb_write(gpio, GPIO_PORTA_EOI, BIT(hwirq));
> +                       val_intmask = dwapb_read(gpio, GPIO_INTMASK);
> +                       dwapb_write(gpio, GPIO_INTMASK, val_intmask | BIT(hwirq));
> +                       val_inten = dwapb_read(gpio, GPIO_INTEN);
> +                       dwapb_write(gpio, GPIO_INTEN, val_inten & ~BIT(hwirq));
> +                       continue;
> +               }
>
>                 if ((irq_type & IRQ_TYPE_SENSE_MASK) == IRQ_TYPE_EDGE_BOTH)
>                         dwapb_toggle_trigger(gpio, hwirq);

Ugh I don't know if that is how you'r supposed to deal with the return value
from generic_handle_irq(), we better get tglx eyes on this.

Yours,
Linus Walleij

Re: [PATCH] gpio: dwapb: Add robust error handling in interrupt handler

[Thomas Gleixner]

On Fri, Jul 03 2026 at 23:21, Linus Walleij wrote:
> On Fri, Jul 3, 2026 at 3:49 PM Liang Hao <haohlliang@gmail.com> wrote:
>
>> The current interrupt handler silently continues if an interrupt
>> handling fails, which may lead to interrupt storms. Add proper
>> error handling to gracefully recover from failed interrupt
>> handling.
>>
>> When generic_handle_irq() fails, the following recovery actions are
>> taken:
>>   - Write EOI to clear the pending interrupt
>>   - Mask the interrupt to prevent immediate re-triggering
>>   - Disable the interrupt to stop further interrupts on this line

This completely fails to explain WHY generic_handle_irq() fails.

There are only two reasons for that:

      1) The interrupt descriptor is not available (EINVAL)

      2) The platform mandates that the interrupt has to be handled in
         hard interrupt context (EPERM). This also emits a warning.

There is also zero information whether the irq mapping lookup returns a
valid interrupt in this scenario, so it's hard to tell what's really
going on.

As there is no mention of the warning I assume that's #1. Which means
this is papering over some underlying problem in that driver. Looking at
the counter measures makes it entirely clear:

    EOI, mask, disable

If there is no interrupt descriptor then the driver failed to mask and
disable the interrupt line at some point.

So this is just a lazy debugging aid for something which is not supposed
to happen in a sane and production ready driver.

Thanks,

        tglx