linux-kernel - Re: [PATCH v2 11/12] drm/sun4i: backend: Make sure we don't have a commit pending

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Message-ID: <CAGb2v66xjXgX4em1=Uv-sAoAX77B86EOgwuv_vYrbJ5015FcwQ@mail.gmail.com>
Date:   Thu, 4 Jan 2018 22:50:49 +0800
From:   Chen-Yu Tsai <wens@...e.org>
To:     Maxime Ripard <maxime.ripard@...e-electrons.com>
Cc:     Daniel Vetter <daniel.vetter@...el.com>,
        David Airlie <airlied@...ux.ie>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
        Neil Armstrong <narmstrong@...libre.com>, thomas@...sch.nl
Subject: Re: [PATCH v2 11/12] drm/sun4i: backend: Make sure we don't have a
 commit pending

On Mon, Dec 18, 2017 at 10:57 PM, Maxime Ripard
<maxime.ripard@...e-electrons.com> wrote:
> If we try to read the backend registers while it fetches the new values, we
> end up with the value of some random register instead of the one we asked
> for.
>
> In order to prevent that, let's make sure that the very first thing we do
> during our atomic modesetting is to let the commit bit come to a rest.
>
> We don't have to worry about anything else since the only time we will
> trigger a new transaction is during the atomic_commit which comes much
> later.
>
> Signed-off-by: Maxime Ripard <maxime.ripard@...e-electrons.com>

Reviewed-by: Chen-Yu Tsai <wens@...e.org>