Re: [PATCH v2] i2c: ls2x-v2: return IRQ_HANDLED after servicing an error

[Andy Shevchenko]

On Wed, May 06, 2026 at 04:40:15PM +0100, David Carlier wrote:
> The event ISR reads SR1 and, when an error flag (ARLO/AF/BERR) is set,
> calls loongson2_i2c_isr_error() which clears the offending flag, issues
> STOP for the AF case, records msg->result, masks every CR2 interrupt
> enable and completes the waiter. The handler then returns IRQ_NONE,
> declaring to the IRQ core that the device did not interrupt.
> 
> That report is wrong. The device did interrupt and the handler fully
> serviced it. Because the IRQ is requested with IRQF_SHARED, the genirq
> spurious-IRQ tracker counts each error as unhandled. A bus that emits
> sporadic NACKs, arbitration losses or bus errors will therefore march
> toward the spurious-IRQ threshold and the line can end up disabled,
> wedging the controller.
> 
> Return IRQ_HANDLED on this path. The other IRQ_NONE site, taken when
> neither an event nor an error bit is set, remains correct.

>From the analysis and code sounds legit,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
but my tag applies only after Loongson people confirm this is correct change.

-- 
With Best Regards,
Andy Shevchenko