Hi Chun-Kuang,

On 30/6/20 18:26, Chun-Kuang Hu wrote:

Hi, Enric:

Enric Balletbo i Serra [off-list ref] 於 2020年6月30日 週二 下午10:34寫道：

quoted

Hi Sam, Chun-Kuan,

On 20/6/20 23:33, Sam Ravnborg wrote:

quoted

Hi Enric

On Mon, Jun 15, 2020 at 10:31:01PM +0200, Enric Balletbo i Serra wrote:

quoted

(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

Regards,
 Enric

Regards,
Chun-Kuang.

quoted

Thanks,
 Enric

quoted

      Sam

quoted

 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@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel