Re: [Qemu-devel] [PATCH] monitor: accept input on resume

[Markus Armbruster]

Marc-André Lureau <address@hidden> writes:

> Hi
>
> On Tue, Jul 31, 2018 at 1:30 PM, Markus Armbruster <address@hidden> wrote:
>> Marc-André Lureau <address@hidden> writes:
>>
>>> A chardev may stop trying to write if the associated can_read()
>>> callback returned 0. This happens when the monitor is suspended.
>>> The frontend is supposed to call qemu_chr_fe_accept_input() when it is
>>> ready to accept data again.
>>>
>>> Signed-off-by: Marc-André Lureau <address@hidden>
>>
>> Impact?
>
> I have observed the issue with a spice port, all pending commands
> aren't flushed. Most chardev don't use the accept_input() callback,
> and instead poll regularly, like char-socket.c:tcp_chr_read_poll()

The ones that do use it are braille, mux, msmouse, spice (abstract),
spicevmc, spiceport, wctablet.

A description of the impact should be worked into the commit message.

>> Is this to be considered for 3.0?
>
> This is not a regression, afaik, and doesn't impact common monitor
> chardev. So it could be delayed. But it's also a small fix for Spice
> chardev that shouldn't create regression, so it should be fine for
> 3.0.

If the callbacks we now call all work fine, we should be good.  But
that's a chardev question, and I'm the guy for the monitor questions.  I
think the decision needs to be made by maintainers of the chardev
subsystem.

Preferably with an improved commit message:
Acked-by: Markus Armbruster <address@hidden>