MIME-Version: 1.0
References: <20230131141756.RFT.v2.1.I723a3761d57ea60c5dd754c144aed6c3b2ea6f5a@changeid>
 <CAPY8ntAUhVB6UtQTeHAcxNW950Ou+NcEoGwk3JnVWLay89_0Nw@mail.gmail.com>
 <CAD=FV=UNx7ivymvpGKcuyvvepvo-T2B2aREJy2GyawTHCnazsw@mail.gmail.com>
 <e077d60d-5881-1ccc-a17a-fbe64392e29d@linaro.org> <CAD=FV=W_FVUOD6T0Lx-JTqrqaP9gPgb4R-2TaSqKwkaBkqHJmQ@mail.gmail.com>
In-Reply-To: <CAD=FV=W_FVUOD6T0Lx-JTqrqaP9gPgb4R-2TaSqKwkaBkqHJmQ@mail.gmail.com>
From:   Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Date:   Thu, 2 Mar 2023 20:19:54 +0200
Message-ID: <CAA8EJpq-gHjtNzDya-50K3mz5Odhgfd=cSKYfNReSnoRf5reTQ@mail.gmail.com>
Subject: Re: [RFT PATCH v2 1/3] drm/bridge: tc358762: Set pre_enable_prev_first
To:     Doug Anderson <dianders@chromium.org>
Cc:     Dave Stevenson <dave.stevenson@raspberrypi.com>,
        dri-devel@lists.freedesktop.org, Rob Clark <robdclark@gmail.com>,
        Abhinav Kumar <quic_abhinavk@quicinc.com>,
        freedreno@lists.freedesktop.org,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Jonas Karlman <jonas@kwiboo.se>, linux-arm-msm@vger.kernel.org,
        Neil Armstrong <neil.armstrong@linaro.org>,
        Robert Foss <robert.foss@linaro.org>,
        Stephen Boyd <swboyd@chromium.org>,
        Vinod Koul <vkoul@kernel.org>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Andrzej Hajda <andrzej.hajda@intel.com>,
        Sean Paul <sean@poorly.run>, linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Thu, 2 Mar 2023 at 19:26, Doug Anderson <dianders@chromium.org> wrote:
>
> Hi,
>
> On Mon, Feb 27, 2023 at 5:24=E2=80=AFPM Dmitry Baryshkov
> <dmitry.baryshkov@linaro.org> wrote:
> >
> > On 28/02/2023 02:26, Doug Anderson wrote:
> > > Hi,
> > >
> > > On Wed, Feb 1, 2023 at 1:51=E2=80=AFAM Dave Stevenson
> > > <dave.stevenson@raspberrypi.com> wrote:
> > >>
> > >> On Tue, 31 Jan 2023 at 22:22, Douglas Anderson <dianders@chromium.or=
g> wrote:
> > >>>
> > >>> Set the "pre_enable_prev_first" as provided by commit 4fb912e5e190
> > >>> ("drm/bridge: Introduce pre_enable_prev_first to alter bridge init
> > >>> order"). This should allow us to revert commit ec7981e6c614
> > >>> ("drm/msm/dsi: don't powerup at modeset time for parade-ps8640") an=
d
> > >>> commit 7d8e9a90509f ("drm/msm/dsi: move DSI host powerup to modeset
> > >>> time").
> > >>
> > >> I see no reference in the TC358762 datasheet to requiring the DSI
> > >> interface to be in any particular state.
> > >> However, setting this flag does mean that the DSI host doesn't need =
to
> > >> power up and down for each host_transfer request from
> > >> tc358762_pre_enable/tc358762_init, so on that basis I'm good with it=
.
> > >>
> > >> Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
> > >>
> > >>> Cc: Dave Stevenson <dave.stevenson@raspberrypi.com>
> > >>> Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > >>> Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
> > >>> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> > >>> ---
> > >>>
> > >>> (no changes since v1)
> > >>>
> > >>>   drivers/gpu/drm/bridge/tc358762.c | 1 +
> > >>>   1 file changed, 1 insertion(+)
> > >>>
> > >>> diff --git a/drivers/gpu/drm/bridge/tc358762.c b/drivers/gpu/drm/br=
idge/tc358762.c
> > >>> index 0b6a28436885..77f7f7f54757 100644
> > >>> --- a/drivers/gpu/drm/bridge/tc358762.c
> > >>> +++ b/drivers/gpu/drm/bridge/tc358762.c
> > >>> @@ -229,6 +229,7 @@ static int tc358762_probe(struct mipi_dsi_devic=
e *dsi)
> > >>>          ctx->bridge.funcs =3D &tc358762_bridge_funcs;
> > >>>          ctx->bridge.type =3D DRM_MODE_CONNECTOR_DPI;
> > >>>          ctx->bridge.of_node =3D dev->of_node;
> > >>> +       ctx->bridge.pre_enable_prev_first =3D true;
> > >>>
> > >>>          drm_bridge_add(&ctx->bridge);
> > >
> > > Abhinav asked what the plan was for landing this [1]. Since this isn'=
t
> > > urgent, I guess the plan is to land patch #1 in drm-misc-next. Then w=
e
> > > sit and wait until it percolates into mainline and, once it does, the=
n
> > > patch #2 and #3 can land.
> > >
> > > Since I have Dave's review I can commit this to drm-misc-next myself.
> > > My plan will be to wait until Thursday or Friday of this week (to giv=
e
> > > people a bit of time to object) and then land patch #1. Then I'll
> > > snooze things for a while and poke Abhinav and Dmitry to land patch #=
2
> > > / #3 when I notice it in mainline. If, at any point, someone comes ou=
t
> > > of the woodwork and yells that this is breaking them then, worst case=
,
> > > we can revert.
> >
> > This plan sounds good to me.
>
> Pushed to drm-misc-next:
>
> 55cac10739d5 drm/bridge: tc358762: Set pre_enable_prev_first
>
> If my math is right then I'd expect that to get into mainline for
> 6.4-rc1. I guess that means it'll be in Linus's tree mid-May. I'll
> schedule a reminder to suggest landing at patches #2 and #3 again in
> late May.

It might be earlier, if msm-next merges drm-misc earlier (e.g. for the
PSR patches).

--=20
With best wishes
Dmitry