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

[Philippe Mathieu-Daudé]

> On 11/7/20 12:51 AM, Peter Maydell wrote:
>> 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: Philippe Mathieu-Daudé <f4bug@amsat.org>