lvds display interlace on I.MX8M board

[coindu]

 HI all

         I meet some problem to display  with dual lvds signal. 

         The screen resolution is 1920x1080 and finally display interlace.  by write data to /dev/fb0  found some clues .

         if i want draw a red line, which X axis=0, but it will display on X axis = 1. 

         if i want draw a read line, which X axis =1 , it will display on X axis = 0.

        for(x = 0; x< height; x++){

                  draw vertical line which axis = X

         }

         the final display will be

         1  0 3 2 5 4 7 6 ...... 1919 1918

         |   |  |   |  |  |  |  | ........  |       |

         |   |  |   |  |  |  |  | ........  |       |

         |   |  |   |  |  |  |  | ........  |       |

         |   |  |   |  |  |  |  | ........  |       |

        has some parameter to fix it ？

[igorpadykov]

Hi coin

there is no lvds on i.MX8M and it is necessary to use solution similar to

how to use ldb/lvds in android8 of imx8mq ? 

Are you able to draw correctly using MX8-DSI-OLED1, described on

AN12189 MX8-DSI-OLED1 for i.MX 8M Evaluation Kit

https://www.nxp.com/docs/en/application-note/AN12189.pdf

Best regards
igor
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[coindu]

       thanks for your reply. 

       I use tc358775 IC to convert mipi-dsi to lvds  signal. our bottom board has a fpc connector with single lvds for 1280x800 screen and a 40-pin connector with dual lvds for 1920x1080 screen.  the little screen with 1280x800 resolution works well, but the big screen display blurry. 

       so write a display test to draw line on the screen. found the reason but i do not know to to deal with it.

[igorpadykov]

one can try patches provided on link (Aug 23, 2018 12:14 AM)

i.MX8M EVK MIPI CSI Camera Frame Rate 

If this will not help suggest to proceed with NXP Professional Services | NXP 

Best regards
igor

[coindu]

Thanks .

           I tried to exchange LVDSA and LVDSB connection sequence ， the odd and even also follow the exchange . it it work and display normal now.