Re: [PATCH 1/2] hw/m68k/q800: Don't connect two qemu_irqs directly to the same input

[Laurent Vivier]

Le 07/11/2020 à 00:51, Peter Maydell a écrit :
> The q800 board code connects both of the IRQ outputs of the ESCC
> to the same pic[3] qemu_irq. Connecting two qemu_irqs outputs directly
> to the same input is not valid as it produces subtly wrong behaviour
> (for instance if both the IRQ lines are high, and then one goes
> low, the PIC input will see this as a high-to-low transition
> even though the second IRQ line should still be holding it high).
> 
> This kind of wiring needs an explicitly created OR gate; add one.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  hw/m68k/q800.c  | 12 ++++++++++--
>  hw/m68k/Kconfig |  1 +
>  2 files changed, 11 insertions(+), 2 deletions(-)
...

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