topic Re: How does IMX8QXP drive a problem with dual channel LVDS? in i.MX Processors

How does IMX8QXP drive a problem with dual channel LVDS?

baijinlong — Wed, 03 Apr 2019 11:00:37 GMT

hi,

On the software 4.9.88 software, I have configured the ldb node, and the corresponding configuration is as follows:

#############################################################

#include "fsl-imx8qxp-mek.dts"

/ {
model = "Freescale i.MX8QXP MEK";
compatible = "fsl,imx8qxp-mek", "fsl,imx8qxp";

lvds0_panel {
compatible = "boe,av123z7m-n11";

port {

panel_lvds0_in: endpoint {
remote-endpoint = <&lvds0_out>;
};
};

port1{
panel_lvds2_in: endpoint {
remote-endpoint = <&lvds2_out>;
};
};
};

};

&ldb1_phy {
status = "okay";
};

&ldb1 {

split-mode;
/*fsl,dual-channel;*/
status = "okay";

lvds-channel@0 {
fsl,data-mapping = "spwg";
fsl,data-width = <24>;

status = "okay";
primary;
port@1 {
reg = <1>;

lvds0_out: endpoint {
remote-endpoint = <&panel_lvds0_in>;
};
};

};

lvds-channel@1 {
fsl,data-mapping = "spwg";
fsl,data-width = <24>;

status = "okay";
primary;
port@1 {
reg = <1>;

lvds2_out: endpoint {
remote-endpoint = <&panel_lvds2_in>;
};
};

};
};

&ldb2_phy {
status = "disabled";
};

&ldb2 {
status = "disabled";
};

###################################################################

But can't drive my screen 1920x720p (the timing I have added to panel-simple.c), the error is reported during initialization, the corresponding error message is as follows:

How can I modify if there is an error in configuring the device tree? I hope to get your help, thank you!

LCD screen manual see attachment。

Re: How does IMX8QXP drive a problem with dual channel LVDS?

igorpadykov — Wed, 03 Apr 2019 23:23:33 GMT

Hi Jinlong

recommended to use Linux L4.14.78 kernel and there is jdi dual-channel LVDS panel example:

fsl-imx8qxp-mek-jdi-wuxga-lvds0-panel.dts\freescale\dts\boot\arm64\arch - linux-imx - i.MX Linux kernel

i.MX 8QXP MEK Display Selection Guide | NXP Community

seems timings may be adjusted in jdi_tx26d202vm0bwa_timing[]

panel-simple.c\panel\drm\gpu\drivers - linux-imx - i.MX Linux kernel

Best regards
igor
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Re: How does IMX8QXP drive a problem with dual channel LVDS?

baijinlong — Mon, 08 Apr 2019 01:15:24 GMT

Thank you for your reply, I try to the kernel version you provide！

Re: How does IMX8QXP drive a problem with dual channel LVDS?

baijinlong — Mon, 08 Apr 2019 01:31:15 GMT

If I want to configure uboot show logo, should how to modify?Single an LVDS we can display properly, don't know what to pass kernel parameters, able to provide the corresponding documents?Thank you very much!

Re: How does IMX8QXP drive a problem with dual channel LVDS?

igorpadykov — Mon, 08 Apr 2019 04:44:16 GMT

for logo questions please create new thread.

Best regards
igor

Re: How does IMX8QXP drive a problem with dual channel LVDS?

baijinlong — Mon, 08 Apr 2019 08:28:38 GMT

I have replaced the latest firmware, but also added a timing reference jdi_tx26d202vm0bwa_timing, but start the error ( imx-drm display-subsystem: parent device of /ldb@562410e0/lvds-channel@0 is not available );The corresponding debugging information in the log. TXT inside;Hope to provide some help!

Re: How does IMX8QXP drive a problem with dual channel LVDS?

baijinlong — Mon, 08 Apr 2019 08:32:08 GMT

Uboot is not a single line running?Should be how to create a new thread for my screen shows up (double an LVDS driver how to add a screen)??

Re: How does IMX8QXP drive a problem with dual channel LVDS?

igorpadykov — Mon, 08 Apr 2019 11:08:24 GMT

logo is configured by #ifdef CONFIG_VIDEO in

uboot//include/configs/imx8qxp_mek.h

imx8qxp_mek.h\configs\include - uboot-imx - i.MX U-Boot

lcd timings by display_info_t const displays[] in

uboot/board/freescale/imx8qxp_mek/imx8qxp_mek.c

imx8qxp_mek.c\imx8qxp_mek\freescale\board - uboot-imx - i.MX U-Boot

Best regards
igor

Re: How does IMX8QXP drive a problem with dual channel LVDS?

baijinlong — Tue, 09 Apr 2019 02:10:25 GMT

Before this I know, because I drive screen is single way an LVDS, already all ok.So also add;Now we use double channel an LVDS driver we screen is there is a problem, can't drive.Is more than the TXT attachment tip error.You said the display of the logo I am an LVDS has shown correctly in a single road, but change the dual channel after an LVDS Gao Qingbing cannot display, driver error...

Re: How does IMX8QXP drive a problem with dual channel LVDS?

baijinlong — Tue, 09 Apr 2019 11:03:25 GMT

The above is my configured for single can display properly when an LVDS - 1280 x480, when I change into a double an LVDS screen, don't know how to configure lvds_configure (int lvds_id) function, switch to dual channel an LVDS (SPLIT MODE), how do I configure? In detail how to modify???????????

Re: How does IMX8QXP drive a problem with dual channel LVDS?

igorpadykov — Tue, 09 Apr 2019 11:35:05 GMT

Hi Jinlong

NXP has special service for helping with software customizations

NXP Professional Services | NXP

Best regards
igor

Re: How does IMX8QXP drive a problem with dual channel LVDS?

jiangyaqiang — Mon, 18 May 2020 03:24:55 GMT

HI Jinlong:

Are you success to display dual channel lvds(1080p) in kernel ?

I found that , when I set to 1080p, the actual resolution is U:1024x768p-0, I use fsl-imx8qm-mek-jdi-wuxga-lvds1-panel.dts for reference.