Re: [PATCH 2/2] serial: 8250_dw: fall back to poll if there's no interrupt

[Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>]

On Wed, Aug 02, 2023 at 11:05:45PM +0800, Jisheng Zhang wrote:
> When there's no irq(this can be due to various reasons, for example,
> no irq from HW support, or we just want to use poll solution, and so
> on), falling back to poll is still better than no support at all.

...

>  	irq = platform_get_irq(pdev, 0);

You will still have an error message. Perhaps you need to replace it with

	irq = platform_get_irq_optional(pdev, 0);

> -	if (irq < 0)
> -		return irq;
> +	if (irq < 0) {
> +		if (irq != -ENXIO)
> +			return irq;
> +		/* no interrupt -> fall back to polling */
> +		irq = 0;
> +	}

This can be slightly modified:

	/* no interrupt -> fall back to polling */
	if (irq == -ENXIO)
		irq = 0;
	if (irq < 0)
		return irq;

-- 
With Best Regards,
Andy Shevchenko