i.MX ProcessorsのトピックRe: mipi-dsi signal problem

mipi-dsi signal problem

hansung_jung — Wed, 24 Apr 2024 00:02:27 GMT

Hi,

I want to use sn65dsi84 to display single dsi as dual lvds on my custom board.

My development environment is imx8qxp in linux kernel 5.15.71.

The problem is that no mipi-dsi signal on board.

I referred to the settings from the imx8qxp-mek.dts file.

This is configuration of my dts.

-------------------------------

&mipi1_dphy {
status = "okay";
};

&mipi1_dsi_host {

status = "okay";

fsl,clock-drop-level = <2>;

panel@0 {

compatible = "panel-lvds";

/* Physical dimensions of active area */

width-mm = <338>;

height-mm = <270>;

data-mapping = "vesa-24";

panel-timing {

/* the hactive and porches in the datasheet are for a single LVDS channel */

/* since we use dual LVDS channel, Horizontal paramter and clock must double*/

clock-frequency = <41238000>;

hactive = <640>;

hsync-len = <10>;

hfront-porch = <70>;

hback-porch = <70>;

vactive = <1024>;

vsync-len = <10>;

vfront-porch = <5>;

vback-porch = <5>;

};

ports {

#address-cells = <1>;

#size-cells = <0>;

port@0 {

reg = <0>;

dual-lvds-odd-pixels;

panel_in_a: endpoint {

remote-endpoint = <&bridge_out_a>;

};

port@1 {

reg = <1>;

dual-lvds-even-pixels;

panel_in_b: endpoint {

remote-endpoint = <&bridge_out_b>;

};

port {

dsi_out_port: endpoint {

remote-endpoint = <&bridge_in>;

data-lanes = <0 1 2 3>;

};

-------------------------------

However, I cannot get a signal from mipi-dsi.

Is there any missing point?

Thank you in advance.

Re: mipi-dsi signal problem

Zhiming_Liu — Wed, 24 Apr 2024 03:03:52 GMT

Hi @hansung_jung

Please refer below rules.

1.Define sn65dsi84 in i2c node

bridge@2c { compatible = "ti,sn65dsi84"; reg = <0x2c>; enable-gpios = <&gpiof 15 GPIO_ACTIVE_HIGH>; ports { #address-cells = <1>; #size-cells = <0>; port@0 { reg = <0>; bridge_in: endpoint { remote-endpoint = <&dsi_out>; data-lanes = <1 2>; }; }; port@2 { reg = <2>; bridge_out: endpoint { remote-endpoint = <&panel_in_lvds>; }; }; }; };

2. Define panel-lvds in root node , not mipi dsi node

/ {

}

panel@0 { compatible = "panel-lvds"; /* Physical dimensions of active area */ width-mm = <338>; height-mm = <270>; data-mapping = "vesa-24"; panel-timing { /* the hactive and porches in the datasheet are for a single LVDS channel */ /* since we use dual LVDS channel, Horizontal paramter and clock must double*/ clock-frequency = <41238000>; hactive = <640>; hsync-len = <10>; hfront-porch = <70>; hback-porch = <70>; vactive = <1024>; vsync-len = <10>; vfront-porch = <5>; vback-porch = <5>; }; ports { #address-cells = <1>; #size-cells = <0>; port@0 { reg = <0>; dual-lvds-odd-pixels; panel_in_a: endpoint { remote-endpoint = <&bridge_out_a>; }; }; port@1 { reg = <1>; dual-lvds-even-pixels; panel_in_b: endpoint { remote-endpoint = <&bridge_out_b>; }; }; }; }; port { dsi_out_port: endpoint { remote-endpoint = <&bridge_in>; data-lanes = <0 1 2 3>; }; }; };

3.Define mipi dsi out node in mipi1_dsi_host

&mipi1_dsi_host { status = "okay"; ports { port@1 { reg = <1>; mipi1_adv_out: endpoint { remote-endpoint = <&adv7535_1_in>; }; }; }; };

Re: mipi-dsi signal problem

hansung_jung — Wed, 24 Apr 2024 04:52:14 GMT

Thanks for your reply.

I tried running it after making some modifications, but it's not working properly.

Error running "drm_of_find_panel_or_bridge" function on "ti-sn65dsi83.c".

More specifically, it happened in the "of_drm_find_panel".

I think it's because of the incorrect kernel configuration.

So could you please check the attached config file(config.txt) and let me know what needs to be revised?

Re: mipi-dsi signal problem

Zhiming_Liu — Wed, 24 Apr 2024 07:14:36 GMT

Hi @hansung_jung

Please enable panel-lvds driver.

CONFIG_DRM_PANEL_LVDS

Re: mipi-dsi signal problem

hansung_jung — Wed, 24 Apr 2024 10:52:47 GMT

Thanks for the reply.

Following your guide, there are no more errors.

However, it still doesn't work.

When I checked the dsi line with the oscilloscope, I couldn't see the signal.

Is there anything else I can look at about why the dsi signal is not transmitting?

And below is current drm list.

Also refer to the attached dts file(sn65dsi84.dts), panel-simple.c and kernel config(config.txt).

----------------------------

root@:~# ls -l /sys/class/drm/
total 0
lrwxrwxrwx 1 root root 0 Apr 28 17:42 card0 -> ../../devices/platform/display-subsystem/drm/card0
lrwxrwxrwx 1 root root 0 Apr 28 17:42 renderD128 -> ../../devices/platform/display-subsystem/drm/renderD128
-r--r--r-- 1 root root 4096 Apr 28 17:42 version
root@:~# ls -l /sys/class/drm/card0/
dev device/ power/ subsystem/ uevent
root@:~# ls -l /sys/class/drm/card0/
total 0
-r--r--r-- 1 root root 4096 May 5 09:56 dev
lrwxrwxrwx 1 root root 0 May 5 09:56 device -> ../../../display-subsystem
drwxr-xr-x 2 root root 0 May 5 09:56 power
lrwxrwxrwx 1 root root 0 Apr 28 17:42 subsystem -> ../../../../../class/drm
-rw-r--r-- 1 root root 4096 Apr 28 17:42 uevent

Re: mipi-dsi signal problem

Zhiming_Liu — Thu, 25 Apr 2024 00:27:13 GMT

Hi @hansung_jung

Please use one typical timing for test and provide kernel log.

Re: mipi-dsi signal problem

hansung_jung — Thu, 25 Apr 2024 06:46:49 GMT

Thanks for your reply.

Follwing your guide, but stiil it doesn't display.

Please check attached log(sn65dsi84_lvds.log).

And the previous panel-simple method was not possible, so I changed the driver to panel-lvds.

Re: mipi-dsi signal problem

Zhiming_Liu — Thu, 25 Apr 2024 07:41:51 GMT

Hi @hansung_jung

Can you add more log print in sn65dsi83 driver and enable debug flag in drivers/gpu/drm/bridge/nwl-dsi.c ? Please check MIPI HOST driver status.

Re: mipi-dsi signal problem

hansung_jung — Thu, 25 Apr 2024 10:10:44 GMT

Thanks for your reply.

I tried to enable debug flag in nwl-dsi.c like below, but it doesn't show debug message.

hansung_jung_0-1714039680071.png

So could you please let me know how to enable debug flag in driver?

Re: mipi-dsi signal problem

Zhiming_Liu — Fri, 26 Apr 2024 01:18:26 GMT

Hi @hansung_jung

The log should contain 'imx-drm display-subsystem', need check dts nodes.

[ 3.155378] imx-drm display-subsystem: bound imx-drm-dpu-bliteng.2 (ops dpu_bliteng_ops) [ 3.163871] imx-drm display-subsystem: bound imx-dpu-crtc.0 (ops dpu_crtc_ops) [ 3.171546] imx-drm display-subsystem: bound imx-dpu-crtc.1 (ops dpu_crtc_ops) [ 3.179325] imx-drm display-subsystem: bound bus@56220000:ldb@562210e0 (ops imx8qxp_ldb_ops) [ 3.187908] [drm:drm_bridge_attach] *ERROR* failed to attach bridge /bus@56220000/dsi_host@56228000 to encoder DSI-89: -19 [ 3.199019] imx-drm display-subsystem: bound 56228000.dsi_host (ops nwl_dsi_component_ops) [ 3.207751] imx-drm display-subsystem: bound bus@56220000:ldb@562410e0 (ops imx8qxp_ldb_ops) [ 3.216240] [drm:drm_bridge_attach] *ERROR* failed to attach bridge /bus@56220000/dsi_host@56248000 to encoder DSI-89: -19 [ 3.227335] imx-drm display-subsystem: bound 56248000.dsi_host (ops nwl_dsi_component_ops) [ 3.236054] [drm] Initialized imx-drm 1.0.0 20120507 for display-subsystem on minor 1

Please include evk dts in your dts or add dc/dpu node like mek.dts

Re: mipi-dsi signal problem

hansung_jung — Fri, 26 Apr 2024 08:35:47 GMT

Thanks for your reply.

Referring to imx8qxp-ss-lvds.dtsi and imx8qxp-ss-dc.dtsi, I tried to activate 'imx-drm display-subsystem' in 2 ways, but it is failed.

The first way is to add 'display-subsystem' in existing dts.

Please refer to the attached subsystem.dts.

In this case, 'imx-drm display-subsystem' log is not displayed.

The second way is to use dpu, refer to the attached 'dpu_subsystem.dts'.

This causes kernel panic.

I am not familiar with it.

So would you please let me know how to enable 'display-subsystem'.

Re: mipi-dsi signal problem

Zhiming_Liu — Sun, 28 Apr 2024 02:24:29 GMT

Hi @hansung_jung

Are you using linux-imx? You can modify imx8qxp-mek.dts and add this video bridge based on ADV7535. Then you don't need modify any driver config and device tree node.

Re: mipi-dsi signal problem

hansung_jung — Tue, 30 Apr 2024 00:52:01 GMT

Thanks to your reply.

As you said, I use linux-imx.

However, base image is different from imx8qxp-mek.dts.

Even I tried to reference the imx8qxp-mek image as much as possible, but display-subsystem log is not displayed.

I think due to a slight difference, my board doesn't work.

Anyway, thanks to your help, it is very helpful to me.

Re: mipi-dsi signal problem

sean33996 — Wed, 05 Jun 2024 05:56:37 GMT

I get the similar error

[drm:drm_bridge_attach] *ERROR* failed to attach bridge /bus@56220000/dsi_host@56228000 to encoder DSI-89: -517

dts:

&mipi0_dphy {

status = "okay";

};

&mipi0_dsi_host {

status = "okay";

ports {

/delete-node/ port@1;

port@1 {

reg = <1>;

mipi0_dsi_out: endpoint {

remote-endpoint = <&edp_bridge_in>;

};

Re: mipi-dsi signal problem

Zhiming_Liu — Wed, 05 Jun 2024 05:59:41 GMT

Hi @sean33996

Modify your edp driver like this patch about lt9211, -517 is caused by incorrect driver sequence.

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/Patch-for-LT9211-bridge-on-i-MX/ta-p/1685417