AnsweredAssumed Answered

HDMI LCD (720x1440) color issue

Question asked by pratik manvar on Aug 30, 2019
Latest reply on Aug 30, 2019 by igorpadykov

We are using I.MX6 Quad core custom board. 

There is a LCD on HDMI with custom resolution of 720x1440.

 

We are not able to see proper colors on LCD. So, regarding this I have two questions.

 

Question-1:

To add the custom resolution of 720x1440, we have added mode for this resolution in "mxc_edid.c" file as below.

-----------------------------------------------------------------------------

const struct fb_videomode mxc_cea_mode[64] = {

   NULL, 60, 720, 1440, 13468, 40, 40, 10, 8, 10, 4, 0,
   FB_VMODE_NONINTERLACED, 0,
}

-----------------------------------------------------------------------------

 

Below the "fbset" command output on board.

-----------------------------------------------------------------------------

mode "720x1440-63"
   # D: 74.250 MHz, H: 91.667 kHz, V: 62.700 Hz
   geometry 720 1440 768 1440 32
   timings 13468 40 40 10 8 10 4
   accel false
   rgba 8/16,8/8,8/0,8/24
endmode

-----------------------------------------------------------------------------

 

My LCD needs 71.05 MHz of clock frequency. For that, what should be the configuration values in "fb_videomode"?

 

Question-2: 

Our LCD supports RGB888 pixel format and 24 bits per pixel. But, in DTS "interface_pix_fmt" does not accept RGB888..!!

Is this OK to provide RGB24 instead of RGB888 or What should be the pixel format? 

We are not able to see proper colors.

 

Below is DTS entry for HDMI.

-----------------------------------------------

mxcfb1: fb@0 {
   compatible = "fsl,mxc_sdc_fb";
   disp_dev = "hdmi";
   interface_pix_fmt = "RGB24";
   mode_str = "720x1440M@60";
   default_bpp = <24>;
   int_clk = <0>;
   late_init = <0>;
   status = "okay";
};

-----------------------------------------------

 

Thank you very much!

 

Regards,

Pratik Manvar

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