Re: [PATCH 2/2] rtc: cmos: Propagate errors from optional IRQ lookup

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] Propagating -EPROBE_DEFER from platform_get_irq_optional() causes a permanent device probe failure because rtc-cmos is registered using platform_driver_probe(), which explicitly forbids deferred probing.
- [High] Propagating parsing errors like -EINVAL bypasses the x86 legacy IRQ fallback, breaking RTC probing on systems with malformed ACPI tables.
--

--- Patch [2]: [PATCH 2/2] rtc: cmos: Propagate errors from optional IRQ lookup ---
commit bf54cacd6dce9cc731cd51fdbcbf8b84af0b1e7f
Author: bui duc phuc <[email protected]>

rtc: cmos: Propagate errors from optional IRQ lookup

The commit updates the RTC CMOS driver to propagate error codes returned by
platform_get_irq_optional() other than -ENXIO, while preserving -1 for the
case where no optional IRQ is available.

> diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
> index fa04ece151b8b..0a2c7383c8cd4 100644
> --- a/drivers/rtc/rtc-cmos.c
> +++ b/drivers/rtc/rtc-cmos.c
> @@ -1436,7 +1436,9 @@ static int __init cmos_platform_probe(struct platform_device *pdev)
>  	else
>  		resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	irq = platform_get_irq_optional(pdev, 0);
> -	if (irq < 0) {
> +	if (irq < 0 && irq != -ENXIO)
> +		return irq;

[Severity: High]
Does propagating -EPROBE_DEFER from platform_get_irq_optional() cause a
permanent device probe failure?

Since rtc-cmos is registered using platform_driver_probe(), which explicitly
forbids deferred probing, returning -EPROBE_DEFER here might cause the driver
core to convert it to -ENXIO and permanently fail the probe instead of
proceeding without an optional IRQ.

[Severity: High]
Does propagating parsing errors like -EINVAL bypass the x86 legacy IRQ
fallback?

On x86 systems with malformed ACPI tables (e.g., specifying IRQ 0, which
platform_get_irq_optional() rejects with -EINVAL), propagating the error
bypasses the fallback logic below that successfully hardcodes the IRQ to
RTC_IRQ if legacy PIC IRQs are supported, potentially breaking RTC probing
on those systems.

> +	if (irq == -ENXIO) {
>  		irq = -1;
>  #ifdef CONFIG_X86
>  		/*

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Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=2