linux-arm-msm.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: Doug Anderson <dianders@chromium.org>
Cc: Rob Clark <robdclark@gmail.com>, Sean Paul <sean@poorly.run>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Abhinav Kumar <abhinavk@codeaurora.org>,
	Stephen Boyd <swboyd@chromium.org>,
	Kuogee Hsieh <khsieh@codeaurora.org>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	Vara Reddy <varar@codeaurora.org>,
	freedreno <freedreno@lists.freedesktop.org>,
	Chandan Uddaraju <chandanu@codeaurora.org>
Subject: Re: [RFC] drm/msm/dp: Allow attaching a drm_panel
Date: Mon, 4 Oct 2021 18:11:11 -0700	[thread overview]
Message-ID: <YVumL1lHLqtb/HKS@ripper> (raw)
In-Reply-To: <CAD=FV=U=xVLuKOYHbGPTkLjGa8_U+F1ZtEvJt4LGaRuR5SsKFw@mail.gmail.com>

On Mon 04 Oct 17:36 PDT 2021, Doug Anderson wrote:

> Hi,
> 
> On Fri, Oct 1, 2021 at 2:00 PM Bjorn Andersson
> <bjorn.andersson@linaro.org> wrote:
> >
> > On Fri 27 Aug 13:52 PDT 2021, Doug Anderson wrote:
> >
> > > Hi,
> > >
> > > On Mon, Jul 26, 2021 at 4:15 PM Bjorn Andersson
> > > <bjorn.andersson@linaro.org> wrote:
> > > >
> > > > +static int dp_parser_find_panel(struct dp_parser *parser)
> > > > +{
> > > > +       struct device_node *np = parser->pdev->dev.of_node;
> > > > +       int rc;
> > > > +
> > > > +       rc = drm_of_find_panel_or_bridge(np, 2, 0, &parser->drm_panel, NULL);
> > >
> > > Why port 2? Shouldn't this just be port 1 always? The yaml says that
> > > port 1 is "Output endpoint of the controller". We should just use port
> > > 1 here, right?
> > >
> >
> > Finally got back to this, changed it to 1 and figured out why I left it
> > at 2.
> >
> > drm_of_find_panel_or_bridge() on a DP controller will find the of_graph
> > reference to the USB-C controller, scan through the registered panels
> > and conclude that the of_node of the USB-C controller isn't a registered
> > panel and return -EPROBE_DEFER.
> 
> I'm confused, but maybe it would help if I could see something
> concrete. Is there a specific board this was happening on?
> 

Right, let's make this more concrete with a snippet from the actual
SC8180x DT.

> Under the DP node in the device tree I expect:
> 
> ports {
>   port@1 {
>     reg = <1>;
>     edp_out: endpoint {
>       remote-endpoint = <&edp_panel_in>;
>     };
>   };
> };
> 

/* We got a panel */
panel {
    ...
    ports {
        port {
            auo_b133han05_in: endpoint {
                remote-endpoint = <&mdss_edp_out>;
            };
        };
    };
};

/* And a 2-port USB-C controller */
type-c-controller {
    ...
    connector@0 {
        ports {
            port@0 {
                reg = <0>;
                ucsi_port_0_dp: endpoint {
                    remote-endpoint = <&dp0_mode>;
                };
            };

            port@1 {
                reg = <1>;
                ucsi_port_0_switch: endpoint {
                    remote-endpoint = <&primary_qmp_phy>;
                };
            };
        };
    };

	connector@1 {
        ports {
            port@0 {
                reg = <0>;
                ucsi_port_1_dp: endpoint {
                    remote-endpoint = <&dp1_mode>;
                };
            };

            port@1 {
                reg = <1>;
                ucsi_port_1_switch: endpoint {
                    remote-endpoint = <&second_qmp_phy>;
                };
            };
        };
	};
};

/* And then our 2 DP and single eDP controllers */
&mdss_dp0 {
    ports {
        port@1 {
            reg = <1>;
            dp0_mode: endpoint {
                remote-endpoint = <&ucsi_port_0_dp>;
            };
        };
    };
};

&mdss_dp1 {
    ports {
        port@1 {
            reg = <1>;
            dp1_mode: endpoint {
                remote-endpoint = <&ucsi_port_1_dp>;
            };
        };
    };
};

&mdss_edp {
    ports {
        port@1 {
            reg = <1>;
            mdss_edp_out: endpoint {
                remote-endpoint = <&auo_b133han05_in>;
            };
        };
    };
};

> If you have "port@1" pointing to a USB-C controller but this instance
> of the DP controller is actually hooked up straight to a panel then
> you should simply delete the "port@1" that points to the typeC and
> replace it with one that points to a panel, right?
> 

As you can see, port 1 on &mdss_dp0 and &mdss_dp1 points to the two UCSI
connectors and the eDP points to the panel, exactly like we agreed.

So now I call:
    drm_of_find_panel_or_bridge(dev->of_node, 1, 0, &panel, NULL);

which for the two DP nodes will pass respective UCSI connector to
drm_find_panel() and get EPROBE_DEFER back - because they are not on
panel_list.

There's nothing indicating in the of_graph that the USB connectors
aren't panels (or bridges), so I don't see a way to distinguish the two
types remotes.

Hope that clarifies my conundrum.

Regards,
Bjorn

  reply	other threads:[~2021-10-05  1:09 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-26 23:13 Bjorn Andersson
2021-07-29  9:59 ` Dmitry Baryshkov
2021-08-25 23:28   ` Bjorn Andersson
2021-08-26  1:31 ` Stephen Boyd
2021-08-26 20:36   ` Doug Anderson
2021-08-26 20:29 ` Doug Anderson
2021-08-27 20:52 ` Doug Anderson
2021-08-28 14:40   ` Bjorn Andersson
2021-08-30 16:01     ` Doug Anderson
2021-10-01 21:02   ` Bjorn Andersson
2021-10-05  0:36     ` Doug Anderson
2021-10-05  1:11       ` Bjorn Andersson [this message]
2021-10-05  1:50         ` Stephen Boyd
2021-10-05  2:11           ` Bjorn Andersson
2021-10-05 15:39         ` Doug Anderson
2021-10-05 17:34           ` Bjorn Andersson
2021-10-05 23:09             ` Doug Anderson
2021-10-06  2:29               ` Bjorn Andersson
2021-10-06 15:12                 ` Doug Anderson
2021-10-06 20:26                   ` Prashant Malani
2021-10-07 10:17                     ` Heikki Krogerus
2021-10-07 16:15                       ` Bjorn Andersson
2021-10-08 12:38                         ` Heikki Krogerus
2021-12-06 22:31                       ` Bjorn Andersson
2021-12-07 12:26                         ` Heikki Krogerus
2021-12-07 16:56                           ` Hans de Goede
2021-12-07 17:29                             ` Bjorn Andersson
2021-12-07 17:54                           ` Imre Deak

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=YVumL1lHLqtb/HKS@ripper \
    --to=bjorn.andersson@linaro.org \
    --cc=abhinavk@codeaurora.org \
    --cc=airlied@linux.ie \
    --cc=chandanu@codeaurora.org \
    --cc=daniel@ffwll.ch \
    --cc=dianders@chromium.org \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=freedreno@lists.freedesktop.org \
    --cc=khsieh@codeaurora.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=robdclark@gmail.com \
    --cc=sean@poorly.run \
    --cc=swboyd@chromium.org \
    --cc=varar@codeaurora.org \
    --subject='Re: [RFC] drm/msm/dp: Allow attaching a drm_panel' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).