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

[Daniel Stone]

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.

>> 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.

>> --- 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