Imx6 Framerate with LVDS split-mode

[shuyuchou]

Hi,

I have 1920x1200 LVDS panel and add "split-mode" in dtsi of i.mx6.

There's cts refreshrate failed on "  android.view.cts.DisplayRefreshRateTest -- testRefreshRate" , the freshrate is only 32 fps.

I do the same test in imx6 bsp and ev board

The followings are test results of testRefreshRate on IMX6 evb:

	Claimed fps	Average Achieve fps
evb Imx6Q ( wsithout split-mode)	60.000004  fps	59 fps
evb Imx6Q (with split-mode)	60.000004  fps	34 fps

Does anyone know how to resolve this problems ?

Is any limitation of  split-mode with resolution on IMX6?

Test info :

Image: Android 6.0. I.MX6 Q(download from NXP i.MX 6 Series Software and Development Tool Resource)

CPU : iMX6Q

EVB info : IMX6 Series SABRE for Smart Devices (detail info)

evb Imx6Q   split-mode  setting :

kernel_imx_/arch/arm/boot/dts/Imx6qdl-sabresd.dtsi

.....

&ldb {

    status = "okay";

    split-mode;

    lvds-channel@0 {

fsl,data-mapping = "spwg";

fsl,data-width = <18>;

            status = "okay";

display-timings {

native-mode = <&timing0>;

timing0: hsd100pxn1 {

clock-frequency = <65000000>;

hactive = <1024>;

vactive = <768>;

hback-porch = <220>;

  hfront-porch = <40>;

vback-porch = <21>;

vfront-porch = <7>;

hsync-len = <60>;

vsync-len = <10>;

};

};

    };

Thanks,

shuyu

[joanxie]

do you mean refeshrate or framerate? the unit of refresh rate is HZ, fps is for frame rate.

[_at]

joanxie‌

Hi Joan Xie,

Same kind of question from me.

I have 1920x720 LVDS panel and add "split-mode" in dtsi of i.mx6.

LVDS panel says: 1920x720 @ 60 = 47.5 Mhz.

Is any limitation of  split-mode (odd/even) with resolution on IMX6?

Can you explain IPU DI0 clock settings and LVDS CH0/CH1 serialize clock settings for split-mode ?

The below settings is not functional:

• IPU1 DI0 clock = 47.5 MHz, LDB CH0 serialzer clock = 166 MHz.
• Screen is not synchronized to full 1920x720 panel

//// **  Not functional *** /////

&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: C123HAN021 {
clock-frequency = <47500000>;
hactive = <1920>;
vactive = <720>;
hback-porch = <20>;
hfront-porch = <40>;
vback-porch = <20>;
vfront-porch = <10>;
hsync-len = <20>;
vsync-len = <10>;

};

};

};

};

The below settings functional but with limitation

• Screen synchronized to full 1920x720
• But 1/3 portion of screen's color is not proper RGB
• 2/3 portion of screen is proper RGB
• IPU1 DI0 clock = 142.5 MHz, LDB (CH0 serialzer clock) = 498 MHz.

//// **  functional with color limitation*** /////

&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: C123HAN021 {
clock-frequency = <142500000>;
hactive = <1920>;
vactive = <720>;
hback-porch = <20>;
hfront-porch = <40>;
vback-porch = <20>;
vfront-porch = <10>;
hsync-len = <20>;
vsync-len = <10>;

};

};

};

};

Please help us to resolve this.

-Ankit.