Date:   Wed, 1 Jul 2020 07:02:27 +0800
From:   Chun-Kuang Hu <chunkuang.hu@...nel.org>
To:     Enric Balletbo i Serra <enric.balletbo@...labora.com>
Cc:     Chun-Kuang Hu <chunkuang.hu@...nel.org>,
        Sam Ravnborg <sam@...nborg.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Collabora Kernel ML <kernel@...labora.com>,
        Jernej Skrabec <jernej.skrabec@...l.net>,
        Nicolas Boichat <drinkcat@...omium.org>,
        Jonas Karlman <jonas@...boo.se>,
        David Airlie <airlied@...ux.ie>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        DRI Development <dri-devel@...ts.freedesktop.org>,
        Neil Armstrong <narmstrong@...libre.com>,
        Andrzej Hajda <a.hajda@...sung.com>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Hsin-Yi Wang <hsinyi@...omium.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [RESEND PATCH v4 0/7] Convert mtk-dsi to drm_bridge API and get
 EDID for ps8640 bridge

Hi, Enric:

Enric Balletbo i Serra <enric.balletbo@...labora.com> 於 2020年7月1日 週三 上午5:02寫道：
>
> Hi Chun-Kuang,
>
> On 30/6/20 18:26, Chun-Kuang Hu wrote:
> > Hi, Enric:
> >
> > Enric Balletbo i Serra <enric.balletbo@...labora.com> 於 2020年6月30日 週二 下午10:34寫道：
> >>
> >> Hi Sam, Chun-Kuan,
> >>
> >> On 20/6/20 23:33, Sam Ravnborg wrote:
> >>> Hi Enric
> >>>
> >>> On Mon, Jun 15, 2020 at 10:31:01PM +0200, Enric Balletbo i Serra wrote:
> >>>> (This resend is to fix some trivial conflicts due the merge window)
> >>>>
> >>>> The PS8640 dsi-to-eDP bridge driver is using the panel bridge API,
> >>>> however, not all the components in the chain have been ported to the
> >>>> drm_bridge API. Actually, when a panel is attached the default panel's mode
> >>>> is used, but in some cases we can't get display up if mode getting from
> >>>> eDP control EDID is not chosen.
> >>>>
> >>>> This series address that problem, first implements the .get_edid()
> >>>> callback in the PS8640 driver (which is not used until the conversion is
> >>>> done) and then, converts the Mediatek DSI driver to use the drm_bridge
> >>>> API.
> >>>>
> >>>> As far as I know, we're the only users of the mediatek dsi driver in
> >>>> mainline, so should be safe to switch to the new chain of drm_bridge API
> >>>> unconditionally.
> >>>>
> >>>> The patches has been tested on a Acer Chromebook R13 (Elm) running a
> >>>> Chrome OS userspace and checking that the valid EDID mode reported by
> >>>> the bridge is selected.
> >>>>
> >>>> Changes in v4:
> >>>> - Remove double call to drm_encoder_init(). (Chun-Kuang Hu)
> >>>> - Cleanup the encoder in mtk_dsi_unbind(). (Chun-Kuang Hu)
> >>>>
> >>>> Changes in v3:
> >>>> - Replace s/bridge/next bridge/ for comment. (Laurent Pinchart)
> >>>> - Add the bridge.type. (Laurent Pinchart)
> >>>> - Use next_bridge field to store the panel bridge. (Laurent Pinchart)
> >>>> - Add the bridge.type field. (Laurent Pinchart)
> >>>> - This patch requires https://lkml.org/lkml/2020/4/16/2080 to work
> >>>>   properly.
> >>>> - Move the bridge.type line to the patch that adds drm_bridge support. (Laurent Pinchart)
> >>>>
> >>>> Changes in v2:
> >>>> - Do not set connector_type for panel here. (Sam Ravnborg)
> >>>>
> >>>> Enric Balletbo i Serra (7):
> >>>>   drm/bridge: ps8640: Get the EDID from eDP control
> >>>>   drm/bridge_connector: Set default status connected for eDP connectors
> >>>>   drm/mediatek: mtk_dsi: Rename bridge to next_bridge
> >>>>   drm/mediatek: mtk_dsi: Convert to bridge driver
> >>>>   drm/mediatek: mtk_dsi: Use simple encoder
> >>>>   drm/mediatek: mtk_dsi: Use the drm_panel_bridge API
> >>>>   drm/mediatek: mtk_dsi: Create connector for bridges
> >>>
> >>> Patch seems ready to apply. Will they be applied to a mediatek tree
> >>> or to drm-misc-next?
> >>> Or shall we take the first two patches via drm-misc-next, and the
> >>> remaning via a mediatek tree? (I hope not)
> >>>
> >>
> >> I think the only concern is from Chun-Kuan regarding patch 7/7 "drm/mediatek:
> >> mtk_dsi: Create connector for bridges" whether we should support the old API or
> >> not, but the discussion stalled.
> >>
> >
> > I get more clear now. In patch 7/7,
> >
> > ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> >                                         DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> >
> > this would call into mtk_dsi_bridge_attach() first, and then call into
> > panel_bridge_attach() next. So panel_bridge_attach() would receive
> > DRM_BRIDGE_ATTACH_NO_CONNECTOR and it return immediately so it does
> > not call drm_panel_attach(). So where do you call drm_panel_attach()?
> >
>
> Why I need to call drm_panel_attach?
>
> I believe drm_panel_attach() was to attach a panel to a connector, but we don't
> need to do this with the new API as the connector is already created and
> attached to the "dummy" encoder.
>
> Makes that sense to you? What do you think will not work if I don't call
> drm_panel_attach?
>
> [1]
> https://elixir.bootlin.com/linux/v5.8-rc3/source/drivers/gpu/drm/drm_panel.c#L101
>

Sorry, I do not notice this. So for patch 7/7,

Reviewed-by: Chun-Kuang Hu <chunkuang.hu@...nel.org>

and I would take this series into my tree later, thanks.

Regards,
Chun-Kuang.

> Regards,
>  Enric
>
>
> > Regards,
> > Chun-Kuang.
> >
> >> Thanks,
> >>  Enric
> >>
> >>
> >>
> >>>       Sam
> >>>
> >>>
> >>>>
> >>>>  drivers/gpu/drm/bridge/parade-ps8640.c |  12 ++
> >>>>  drivers/gpu/drm/drm_bridge_connector.c |   1 +
> >>>>  drivers/gpu/drm/mediatek/mtk_dsi.c     | 269 ++++++++-----------------
> >>>>  3 files changed, 97 insertions(+), 185 deletions(-)
> >>>>
> >>>> --
> >>>> 2.27.0
> >>>>
> >>>> _______________________________________________
> >>>> dri-devel mailing list
> >>>> dri-devel@...ts.freedesktop.org
> >>>> https://lists.freedesktop.org/mailman/listinfo/dri-devel
> >>>
> >

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