Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Wei Huang <wei@redhat.com>]

On 02/01/2016 04:17 AM, Igor Mammedov wrote:
> On Fri, 29 Jan 2016 09:13:15 -0600
> Wei Huang <wei@redhat.com> wrote:
> 
>> On 01/29/2016 08:50 AM, Peter Maydell wrote:
>>> On 29 January 2016 at 14:46, Shannon Zhao <shannon.zhao@linaro.org> wrote:  
>>>> On 2016/1/29 22:35, Wei Huang wrote:  
>>>>> On 01/29/2016 04:10 AM, Shannon Zhao wrote:  
>>>>>> This makes ACPI work well but makes DT not work. The reason is systemd or
>>>>>> acpid open /dev/input/event0 failed. So the interrupt could be injected
>>>>>> and
>>>>>> could see under /proc/interrupts but guest doesn't have any action. I'll
>>>>>> investigate why it opens failed later.  
>>>>>
>>>>>
>>>>> That is interesting. Could you try it with the following? This reverses
>>>>> the order to down-up and worked on ACPI case.
>>>>>  
>>>> Yeah, that's very weird.
>>>>  
>>>>> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);
>>>>> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);
>>>>>  
>>>> I'll try this tomorrow. But even if this works, it's still weird.  
>>>
>>> I wonder if we should be asserting the GPIO pin in the powerdown-request
>>> hook and then deasserting it on system reset somewhere...  
>>
>> This is another possibility. We can try to reset the pl061 state by
>> hooking up with dc->reset and see what happens.
> I think that's what we do on x86.

So the device state is wrong after reset. I just sent out a fix for it,
which was verified on ACPI code path. Basically the old_in_data is stale
after reboot, causing QEMU to believe that it isn't necessary to raise
up IRQ again for the second reboot/shutdown (see s->old_in_data ^
s->data in pl061.c file).

Shannon: could you double check from your side with my patch?

-Wei

> 
>>
>>>
>>> thanks
>>> -- PMM
>>>   
>>
>