[PATCH v2 4/6] drm/bridge: ti-sn65dsi86: Wrap panel with panel-bridge

[Stephen Boyd]

Quoting Rob Clark (2021-08-11 09:20:30)
> On Wed, Aug 11, 2021 at 5:15 AM Laurent Pinchart
> <laurent.pinchart at ideasonboard.com> wrote:
> >
> > Hi Stephen,
> >
> > On Tue, Aug 10, 2021 at 10:26:33PM -0700, Stephen Boyd wrote:
> > > Quoting Laurent Pinchart (2021-06-23 17:03:02)
> > > > To simplify interfacing with the panel, wrap it in a panel-bridge and
> > > > let the DRM bridge helpers handle chaining of operations.
> > > >
> > > > This also prepares for support of DRM_BRIDGE_ATTACH_NO_CONNECTOR, which
> > > > requires all components in the display pipeline to be represented by
> > > > bridges.
> > > >
> > > > Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>
> > > > Reviewed-by: Jagan Teki <jagan at amarulasolutions.com>
> > > > ---
> > >
> > > With this patch applied I get two eDP devices on Lazor sc7180 (it is the
> > > arch/arm64/boot/dts/qcom/sc7180-trogdor-lazor*.dts files if you're
> > > looking for more info). As far as I can tell, we should only have one
> > > eDP device on the board, for the bridge.
> > >
> > > localhost ~ # ls -l /sys/class/drm/card1-eDP*
> > > lrwxrwxrwx. 1 root root 0 Aug 10 22:24 /sys/class/drm/card1-eDP-1 ->
> > > ../../devices/platform/soc at 0/ae00000.mdss/drm/card1/card1-eDP-1
> > > lrwxrwxrwx. 1 root root 0 Aug 10 22:24 /sys/class/drm/card1-eDP-2 ->
> > > ../../devices/platform/soc at 0/ae00000.mdss/drm/card1/card1-eDP-2
> >
> > Indeed.
> >
> > Does the display driver use the DRM connector bridge helper and
> > DRM_BRIDGE_ATTACH_NO_CONNECTOR on that platform ?
> >
>
> There haven't been any recent changes about how we attach the bridge,
> it doesn't pass DRM_BRIDGE_ATTACH_NO_CONNECTOR.. tbh I've not been
> having time to follow too closely the recent changes with bridge stuff
> myself.
>
> But now with this patch we have both the ti bridge and the panel
> bridge creating a connector..  removing the connector created by the
> ti bridge "fixes" things, but not sure if that would break something
> on other platforms.  I guess there should now always be a panel
> bridge, so removing ti_sn_bridge_connector_init() would be a sane
> thing to do?
>

So this patch works. We don't want to make the connector in this driver
for the next bridge because this driver is making the connector. I guess
eventually we'll drop this flag when this driver stops making the
connector here?

---8<---
diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
index cd0fccdd8dfd..a8d4818484aa 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -741,7 +741,7 @@ static int ti_sn_bridge_attach(struct drm_bridge *bridge,

 	/* Attach the next bridge */
 	ret = drm_bridge_attach(bridge->encoder, pdata->next_bridge,
-				&pdata->bridge, flags);
+				&pdata->bridge, flags | DRM_BRIDGE_ATTACH_NO_CONNECTOR);
 	if (ret < 0)
 		goto err_dsi_detach;