How does IMX8QXP drive a problem with dual channel LVDS?

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How does IMX8QXP drive a problem with dual channel LVDS?

1,234 Views
baijinlong
Contributor III

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:

pastedImage_5.png

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。

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11 Replies

408 Views
igorpadykov
NXP TechSupport
NXP TechSupport

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 ker... 

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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baijinlong
Contributor III

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!

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408 Views
igorpadykov
NXP TechSupport
NXP TechSupport

for logo questions please create new thread.

Best regards
igor

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408 Views
baijinlong
Contributor III

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)??

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igorpadykov
NXP TechSupport
NXP TechSupport

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

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408 Views
baijinlong
Contributor III

pastedImage_1.png

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???????????

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408 Views
jiangyaqiang
Contributor III

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.

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408 Views
igorpadykov
NXP TechSupport
NXP TechSupport

Hi Jinlong

NXP has special service for helping with software customizations

NXP Professional Services | NXP 

Best regards
igor

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408 Views
baijinlong
Contributor III

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...

                       pastedImage_3.png

                 pastedImage_2.png

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408 Views
baijinlong
Contributor III

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!

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408 Views
baijinlong
Contributor III

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

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