Re: [Qemu-devel] qemu_power_down_request handling

[Alexander Graf]

On 16.04.2012, at 11:11, Bhushan Bharat-R65777 wrote:

> 
> 
>> -----Original Message-----
>> From: Alexander Graf [mailto:address@hidden
>> Sent: Monday, April 16, 2012 1:47 PM
>> To: Bhushan Bharat-R65777
>> Cc: address@hidden; Wood Scott-B07421
>> Subject: Re: qemu_power_down_request handling
>> 
>> 
>> On 16.04.2012, at 10:07, Bhushan Bharat-R65777 wrote:
>> 
>>> Hi All,
>>> 
>>> The "-watchdog-action shutdown" uses the monitor system_shutdown mechanism 
>>> but
>> this does not actually powerdown the system.
>>> 
>>> In code, If there is pending powerdown_request
>> (qemu_system_powerdown_request() called) then it try to raise an irq. What is
>> that irq supposed to do. Currently it in NULL pointer so does not do 
>> anything.
>>> 
>>> Code snapshot -- vl.c : main_loop_should_exit()
>>> 
>>> ....
>>>   if (qemu_powerdown_requested()) {
>>>       monitor_protocol_event(QEVENT_POWERDOWN, NULL);
>>>       qemu_irq_raise(qemu_system_powerdown);
>>>   }
>>> . . . .
>>> 
>>> Is the powerdown_request handling not complete?
>> 
>> The watchdog shutdown event is a soft power off. Imagine a PC where you press
>> the power button, the OS gets notified through ACPI that it's supposed to 
>> shut
>> down and shuts down the machine.
>> 
>> I don't know of any BookE system that has a comparable mechanism. We could
>> implement it through qemu-ga and fall back to hard power off maybe?
> 
> Till someone develop this interface, does it make sense to use 
> qemu_system_shutdown_request() rather than qemu_system_powerdown_request() 
> for "-watchdog-action shutdown" ?

I think it makes sense to just register the shutdown callback as powerdown hook 
in the e500 machine :).


Alex