Re: [PATCH 05/18] tty: serial: samsung_tty: add support for Apple UARTs

Hector Martin 'marcan'
2021-02-07T09:28:03Z

On 07/02/2021 18.12, Hector Martin 'marcan' wrote:
> On 06/02/2021 22.15, Marc Zyngier wrote:
>> The default should be IRQ_NONE, otherwise the kernel cannot detect a
>> screaming spurious interrupt.
>
> Good point, and this needs fixing in s3c64xx_serial_handle_irq too then
> (which is what I based mine off of).
>
>>> + ret = request_irq(port->irq, apple_serial_handle_irq, IRQF_SHARED,
>>> + s3c24xx_serial_portname(port), ourport);
>>
>> Why IRQF_SHARED? Do you expect any other device sharing the same line
>> with this UART?
>
> This also came from s3c64xx_serial_startup and... now I wonder why that
> one needs it. Maybe on some SoCs it does get shared? Certainly not for
> discrete rx/tx irq chips (and indeed those don't set the flag)...
>
> CCing Thomas, who added the S3C64xx support (and should probably review
> this patch); is there a reason for IRQF_SHARED there? NB: v1 breaks the
> build on arm or with CONFIG_PM_SLEEP, those will be fixed for v2.

Seems Thomas does not work for Linaro any more :)

CCing Krzysztof instead, who is the Samsung arch maintainer.

>
> Either way, certainly not for Apple SoCs; I'll get rid of IRQF_SHARED
> for v2.

--
Hector Martin "marcan" (marcan@marcan.st)
Public Key: https://mrcn.st/pub