Re: [PATCH v2 17/20] mac_via: always clear ADB interrupt when switching to A/UX mode

[Laurent Vivier <laurent@vivier.eu>]

Le 09/09/2023 à 11:48, Mark Cave-Ayland a écrit :
> When the NetBSD kernel initialises it can leave the ADB interrupt asserted
> depending upon where in the ADB poll cycle the MacOS ADB interrupt handler
> is when the NetBSD kernel disables interrupts.
> 
> The NetBSD ADB driver uses the ADB interrupt state to determine if the ADB
> is busy and refuses to send ADB commands unless it is clear. To ensure that
> this doesn't happen, always clear the ADB interrupt when switching to A/UX
> mode to ensure that the bus enumeration always occurs.
> 
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> ---
>   hw/misc/mac_via.c | 9 +++++++++
>   1 file changed, 9 insertions(+)
> 
> diff --git a/hw/misc/mac_via.c b/hw/misc/mac_via.c
> index 398e8d1967..5d1adf5863 100644
> --- a/hw/misc/mac_via.c
> +++ b/hw/misc/mac_via.c
> @@ -875,6 +875,15 @@ static void via1_auxmode_update(MOS6522Q800VIA1State *v1s)
>       if (irq != oldirq) {
>           trace_via1_auxmode(irq);
>           qemu_set_irq(v1s->auxmode_irq, irq);
> +
> +        /*
> +         * Clear the ADB interrupt. MacOS can leave VIA1B_vADBInt asserted
> +         * (low) if a poll sequence doesn't complete before NetBSD disables
> +         * interrupts upon boot. Fortunately NetBSD switches to the so-called
> +         * "A/UX" interrupt mode after it initialises, so we can use this as
> +         * a convenient place to clear the ADB interrupt for now.
> +         */
> +        s->b |= VIA1B_vADBInt;
>       }
>   }
>   

Reviewed-by: Laurent Vivier <laurent@vivier.eu>