topic IMX6Q LVDS split mode color wrong. in i.MX Processors

IMX6Q LVDS split mode color wrong.

比特卡 — Mon, 05 Nov 2018 10:26:18 GMT

Hi,

In my imx6q board, I use 2 lvds channels to support 1920X720. The dts file is modified as below:

mxcfb1: fb@0 {
compatible = "fsl,mxc_sdc_fb";
disp_dev = "ldb";
interface_pix_fmt = "RGB24";
default_bpp = <32>;
。。。
};

&ldb {
status = "okay";
split-mode;
lvds-channel@0 {
fsl,data-mapping = "spwg";
fsl,data-width = <24>;
primary;
status = "okay";
display-timings {
native-mode = <&timing0>;
timing0: hsd100pxn1 {
clock-frequency = <170000000>;
hactive = <1920>;
vactive = <720>;
hback-porch = <40>;
hfront-porch = <20>;
vback-porch = <40>;
vfront-porch = <20>;
hsync-len = <4>;
vsync-len = <12>;
};
};
};
lvds-channel@1 {
fsl,data-mapping = "spwg";
fsl,data-width = <24>;
status = "okay";
display-timings {
native-mode = <&timing1>;
timing1: hsd100pxn1 {
clock-frequency = <170000000>;
hactive = <1920>;
vactive = <720>;
hback-porch = <40>;
hfront-porch = <20>;
vback-porch = <40>;
vfront-porch = <20>;
hsync-len = <4>;
vsync-len = <12>;
};
};
};
};

And the UBoot bootargs is：

setenv mmcargs 'setenv bootargs console=${console},${baudrate} ${smp} root=${mmcroot} video=mxcfb0:dev=ldb,if=RGB32,bbp=32 video=mxcfb1:off video=mxcfb2:off video=mxcfb3:off'

I use Yocto，and BSP version is L4.9.11。

The screen is Hannstart HSD123KPW2-D10。（datasheet is attached below.）

The wrong color(my board+lvds) and right color(MCIMX6Q-SDB+HDMI) snapshot pics are attached.

below is right color in MCIMX6Q-SDB+HDMI

below is wrong color in my board. The two systems have the same kernel and rootfs.

I have tried some parameters in dts file, the problem still exist.

Could you please provide some advice?

Thanks a million!

Re: IMX6Q LVDS split mode color wrong.

igorpadykov — Tue, 06 Nov 2018 03:15:00 GMT

for rgb24 usage with lvds one can look at below threads and adapt for own codes

iMX6QD How to Add 24-bit LVDS Support in Android

https://community.nxp.com/thread/320314#comments

Best regards
igor
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Re: IMX6Q LVDS split mode color wrong.

比特卡 — Sat, 10 Nov 2018 03:34:41 GMT

hi，Igorpadykov,

Thank You for your help!

The problem which I'm facing is like below:

https://community.nxp.com/thread/384484

Thanks alot！

Re: IMX6Q LVDS split mode color wrong.

比特卡 — Thu, 15 Nov 2018 01:33:38 GMT

This issue has been fixed. The root cause is LVDS DATA line inverted.