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In-Reply-To: <20180110160732.7722-2-gustavo@padovan.org>
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From: Alexandre Courbot <acourbot@chromium.org>
Date: Mon, 15 Jan 2018 16:11:53 +0900
Message-ID: <CAPBb6MV6ErW-Z7n1aK55TxJNRDkt2SkWGEJiXkxrLmZ_GabJOA@mail.gmail.com>
Subject: Re: [PATCH v7 1/6] [media] vb2: add is_unordered callback for drivers
To: Gustavo Padovan <gustavo@padovan.org>
Cc: Linux Media Mailing List <linux-media@vger.kernel.org>,
        Hans Verkuil <hverkuil@xs4all.nl>,
        Mauro Carvalho Chehab <mchehab@osg.samsung.com>,
        Shuah Khan <shuahkh@osg.samsung.com>,
        Pawel Osciak <pawel@osciak.com>,
        Sakari Ailus <sakari.ailus@iki.fi>,
        Brian Starkey <brian.starkey@arm.com>,
        Thierry Escande <thierry.escande@collabora.com>,
        linux-kernel@vger.kernel.org,
        Gustavo Padovan <gustavo.padovan@collabora.com>
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Sender: linux-kernel-owner@vger.kernel.org

On Thu, Jan 11, 2018 at 1:07 AM, Gustavo Padovan <gustavo@padovan.org> wrote:
> From: Gustavo Padovan <gustavo.padovan@collabora.com>
>
> Explicit synchronization benefits a lot from ordered queues, they fit
> better in a pipeline with DRM for example so create a opt-in way for
> drivers notify videobuf2 that the queue is unordered.
>
> Drivers don't need implement it if the queue is ordered.

This is going to make user-space believe that *all* vb2 drivers use
ordered queues by default, at least until non-ordered drivers catch up
with this change. Wouldn't it be less dangerous to do the opposite
(make queues non-ordered by default)?