Re: [Qemu-devel] [PATCH v2 13/14] sm501: Add reset function and vmstate descriptor

[Peter Maydell]

On 2 March 2017 at 20:55, BALATON Zoltan <address@hidden> wrote:
> On Thu, 2 Mar 2017, Peter Maydell wrote:
>>
>> On 2 March 2017 at 20:18, BALATON Zoltan <address@hidden> wrote:
>>>
>>> On Thu, 2 Mar 2017, Peter Maydell wrote:
>>>>
>>>>
>>>> Don't use qemu_register_reset(). Set the appropriate dc->reset
>>>> function pointers instead.
>>>
>>>
>>>
>>> Any reason for that? This way I could save two more boilerplate functions
>>> because I could define reset function once, otherwise I'd need two
>>> versions
>>> taking sysbus and pci states just to extract the SM501State function and
>>> call this function. Do you still think I should do that instead?
>>
>>
>> qemu_register_reset is a pre-QOM method for doing reset;
>> the standard QOM way of saying "my device has some reset
>> behaviour" is to set its reset method pointer.
>> Code calling qemu_register_reset() is generally either (a) doing
>> something kind of weird or (b) old device code that hasn't yet
>> been converted to QOM.
>
>
> Hmm, does having a device with both sysbus and pci versions qualify as
> weird? Does adding a comment saying that this way we don't need two more
> reset functions just to call the registered one justifies using
> qemu_register_reset() or this function is deprecated and should not be used
> and should go with the separate reset functions instead?

Just use the QOM reset method pointers. Every QOM device should have
a reset method, and that should be how it gets
reset. (PCI is special anyway, it needs to get reset when
the guest does a PCI bus reset, and that results in your
device's reset method getting called. Functions registered
with qemu_register_reset() only get called for full system reset.)

thanks
-- PMM