STM32MP1) How to add HDMI extra mode?

[hochul yoo]

Hello everyone ~

​

My custom board has RGB(LTDC) and HDMI display interfaces. 

We want to display same screen on same time.(duplicate mode)

So, LTDC interface connected to local LCD and HDMI transmitter(sii9022).

&ltdc node of my dts is below ..

&ltdc{
	pinctrl-names = "default", "sleep";
	pinctrl-0 = <&ltdc_pins_mx>;
	pinctrl-1 = <&ltdc_sleep_pins_mx>;
	status = "okay";
 
	/* USER CODE BEGIN ltdc */
 port {
		#address-cells = <1>;
		#size-cells = <0>;
 
 ltdc_ep0_out: endpoint@0 {
			reg = <0>;			
 remote-endpoint = <&sii9022_in>;
		}; 
	};
	/* USER CODE END ltdc */
};

and we can display both screen successfully as below picture. 

However, unfortunately my LCD`s resolution is 1280x800.

and linux platform doesn't have this HDMI resolution mode.

so my LCD was displayed as below...

Therefore, I want to add 1280x800 mode to HDMI. 

Is there any guide article on wiki?

Thanks a lot !!!

[hochul yoo]

My clock configuration was problem.

Below linked question was very helpful to me, thanks.

https://community.st.com/s/question/0D50X0000BNscKZSQZ/what-is-the-criteria-for-modetest-to-accept-a-modeline​

[Kim KyungTack]

https://community.st.com/s/question/0D50X0000BNscKZSQZ/what-is-the-criteria-for-modetest-to-accept-a-modeline