[PATCH v2 0/7] drm/exynos: add pm runtime support

[Inki Dae]

Hi Daniel,


2015-11-21 22:40 GMT+09:00 Daniel Stone <daniel at fooishbar.org>:
> Hi Inki,
>
> On 21 November 2015 at 09:38, Inki Dae <daeinki at gmail.com> wrote:
>> 2015-11-21 1:44 GMT+09:00 Javier Martinez Canillas <javier at osg.samsung.com>:
>>> On 11/20/2015 08:13 AM, Inki Dae wrote:
>>>> The boot log says,
>>>> [    5.754493] vdd_ldo9: supplied by vdd_2v
>>>> [    5.765510] of_graph_get_next_endpoint(): no port node found in /dp-controller at 145B0000
>>>>
>>>
>>> This message is a red herring for the reported issue, the message is also
>>> present when the machine boots and the display is brought correctly.
>>>
>>>> Seems this error is because exynos5800-peach-pit.dts file doesn't have 'ports' node in dp node.
>>>>
>>>> Below is dp node description of exynos5420-peach-pit.dts file.
>>>> &dp {
>>>>       status = "okay";
>>>>       pinctrl-names = "default";
>>>>       pinctrl-0 = <&dp_hpd_gpio>;
>>>>       samsung,color-space = <0>;
>>>>       samsung,dynamic-range = <0>;
>>>>       samsung,ycbcr-coeff = <0>;
>>>>       samsung,color-depth = <1>;
>>>>       samsung,link-rate = <0x06>;
>>>>       samsung,lane-count = <2>;
>>>>       samsung,hpd-gpio = <&gpx2 6 GPIO_ACTIVE_HIGH>;
>>>>
>>>>       ports {
>>>>               port at 0 {
>>>>                       dp_out: endpoint {
>>>>                               remote-endpoint = <&bridge_in>;
>>>>                       };
>>>>               };
>>>>       };
>>>> };
>>>>
>>>> And below is for exynos5800-peash-pit.dts,
>>>> &dp {
>>>>       status = "okay";
>>>>       pinctrl-names = "default";
>>>>       pinctrl-0 = <&dp_hpd_gpio>;
>>>>       samsung,color-space = <0>;
>>>>       samsung,dynamic-range = <0>;
>>>>       samsung,ycbcr-coeff = <0>;
>>>>       samsung,color-depth = <1>;
>>>>       samsung,link-rate = <0x0a>;
>>>>       samsung,lane-count = <2>;
>>>>       samsung,hpd-gpio = <&gpx2 6 GPIO_ACTIVE_HIGH>;
>>>>       panel = <&panel>;
>>>> };
>>>>
>>>
>>> The difference is because the Exynos5420 Peach Pit Display Port is not
>>> attached directly to the display panel, there is an eDP/LVDS bridge chip
>>> in the middle (PS8622) while the Exynos5800 Peach Pi doesn't have that.
>>>
>>> The Exynos DP driver lookups for either a panel phandle or an OF graph
>>> endpoint that points to a bridge chip and the bridge enpoint has a port
>>> that points to the panel.
>>>
>>> So the DT is correct but of_graph_get_next_endpoint() always prints an
>>
>> Then, the DT is really incorrect. As you mentioned, if the Exynos5800 Peach PI
>> board doesn't use eDP, then the dp node __should be removed__ from
>> exynos5800-peach-pit.dts.
>>
>> From a common-sense standpoint, there is no any reason to build
>> and probe dp driver if the board doesn't use dp hardware.
>
> I agree with what you say, but unfortunately you've slightly misread
> what Javier has said. :) exynos5420-peach-pit has an LVDS panel, with
> the eDP -> LVDS bridge in between (ps8622). exynos5800-peach-pi (from
> which I am writing this) has an eDP panel directly connected. The DT
> describes both the eDP connector from FIMD and the eDP panel, except
> that there is no connection between the DT nodes.

Right. I misread what Javier said. :)

>
>>> error if the port so OF graph endpoints it seems can't be optional as
>>> used in this driver. Maybe that message should be change to debug then?
>>>
>>> Another option is to extend the DP driver DT binding to be more generic
>>> supporting having a port to a panel besides a bridge, so we could have
>>> something like this for Exynos5800 Peach and be consistent in both cases:
>>
>> It's really not good. This would make it more complex. The best
>> solution is just to
>> remove the dt node from the device tree file.
>
> Given the above, not really. Javier's patch seems correct to me - as
> you can see, there is a panel node, and that is the panel that's
> really connected.

Indeed. Javier's patch will correct it.

Thanks,
Inki Dae

>
>>> --- a/arch/arm/boot/dts/exynos5800-peach-pi.dts
>>> +++ b/arch/arm/boot/dts/exynos5800-peach-pi.dts
>>> @@ -122,6 +122,12 @@
>>>                 compatible = "auo,b133htn01";
>>>                 power-supply = <&tps65090_fet6>;
>>>                 backlight = <&backlight>;
>>> +
>>> +               port {
>>> +                       panel_in: endpoint {
>>> +                               remote-endpoint = <&dp_out>;
>>> +                       };
>>> +               };
>>>         };
>>>
>>>         mmc1_pwrseq: mmc1_pwrseq {
>>> @@ -148,7 +154,14 @@
>>>         samsung,link-rate = <0x0a>;
>>>         samsung,lane-count = <2>;
>>>         samsung,hpd-gpio = <&gpx2 6 GPIO_ACTIVE_HIGH>;
>>> -       panel = <&panel>;
>>> +
>>> +       ports {
>>> +               port at 0 {
>>> +                       dp_out: endpoint {
>>> +                               remote-endpoint = <&panel_in>;
>>> +                       };
>>> +               };
>>> +       };
>>>  };
>
> Cheers,
> Daniel