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From: Markus Armbruster <armbru@redhat.com>
References: <20181122071613.2889-1-kraxel@redhat.com>
	<87h8g4lyyh.fsf@dusky.pond.sub.org>
	<20181126151325.2pfues2q7vuqin4y@sirius.home.kraxel.org>
Date: Mon, 26 Nov 2018 17:58:00 +0100
In-Reply-To: <20181126151325.2pfues2q7vuqin4y@sirius.home.kraxel.org> (Gerd
	Hoffmann's message of "Mon, 26 Nov 2018 16:13:25 +0100")
Message-ID: <87zhtvixnr.fsf@dusky.pond.sub.org>
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Subject: Re: [Qemu-devel] [PATCH v3] qapi: add query-display-options command
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To: Gerd Hoffmann <kraxel@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>, qemu-devel@nongnu.org

Gerd Hoffmann <kraxel@redhat.com> writes:

> On Mon, Nov 26, 2018 at 03:01:42PM +0100, Markus Armbruster wrote:
>> Gerd Hoffmann <kraxel@redhat.com> writes:
>> 
>> > Add query-display-options command, which allows querying the qemu
>> > display configuration, and -- as an intentional side effect -- makes
>> > DisplayOptions discoverable via query-qmp-schema so libvirt can go
>> > figure which display options are supported.
>> >
>> > Use case: commit d4dc4ab1 added rendernode parameter for egl-headless.
>> 
>> I understand why exposing DisplayOptions in query-qmp-schema is useful.
>> But can you think of a use for the new command?
>> 
>> If not, then this is a workaround for lack of CLI introspection.
>> That's okay, ball's in my court on that.  But I'd like to have the
>> "workaroundness" spelled out in the commit message then.
>
> Sure.  I assumed the "intentional side effect" message is clear enough
> though.
>
> The command itself isn't that helpful, you should know how you have
> started qemu ...

If it's not too much trouble, please tweak the commit message to be a
bit more explicit.  Perhaps:

    Add query-display-options command, which allows querying the qemu
    display configuration.  This isn't particularly useful, except it
    exposes QAPI type DisplayOptions in query-qmp-schema, so that
    libvirt can discover recently added -display parameter rendernode
    (commit d4dc4ab133b).  Works around lack of sufficiently powerful
    command line introspection.

This should give me a fighting chance to remember deprecating the
command once we got sufficiently powerful command line introspection.