Re: [PATCH for-8.0 0/2] hw/input/ps2: Convert to 3-phase reset

[Mark Cave-Ayland]

On 09/11/2022 17:00, Peter Maydell wrote:

> This patchset converts the ps2 keyboard and mouse devices to 3-phase
> reset. The rationale here is that it would be nice to get rid of the
> device_class_set_parent_reset() function, which is used by
> legacy-reset subclasses which want to chain to their parent's reset
> function. There aren't very many of these devices in total, and if we
> convert them all to 3-phase reset they can use the 3-phase-reset
> equivalent (resettable_class_set_parent_phases()).  Eventually this
> will then let us simplify the transitional code for handling old-style
> device reset.
>
> This is one of a number of patchsets to do this that I'm planning to
> write and send out over the next few weeks. It's all 8.0 material.
>
> thanks
> -- PMM
>
> Peter Maydell (2):
>    hw/input/ps2: Convert TYPE_PS2_DEVICE to 3-phase reset
>    hw/input/ps2.c: Convert TYPE_PS2_{KBD,MOUSE}_DEVICE to 3-phase reset
>
>   include/hw/input/ps2.h |  2 +-
>   hw/input/ps2.c         | 45 +++++++++++++++++++++++++++++-------------
>   2 files changed, 32 insertions(+), 15 deletions(-)

I haven't used the new ResettableClass myself previously, however it seems to match 
the excellent documentation at https://qemu.readthedocs.io/en/latest/devel/reset.html 
so feel free to add my Acked-by tag.

One part that did stand out to me in the docs is the part that reads "For now 
migration of a device or bus in reset is not supported. Care must be taken not to 
delay resettable_release_reset() after its resettable_assert_reset() counterpart". Is 
this still a valid concern and something we need to think about? I'm thinking about 
if a guest triggers a SCSI bus or PCI bus reset for example.


ATB,

Mark.