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i.mx6 output bt1120 720P video, has some problem

Question asked by Zi Li on Aug 20, 2018
Latest reply on Aug 24, 2018 by Zi Li

We currently use imx6 -> adv7390 to output CVBS 480i video. We want to upgrade the resolution, so we change adv7390 to pt1000 to output 720P video.


The datasheet of pt1000 says that pt1000 can input with bt656 or bt1120 and output from 480i to 1080i AHD signal.


We have tested following situation:

1. imx6--BT656-->pt1000, output 480i is OK.

2. imx6--BT1120-->pt1000, output 720P or 1080i ,can't dislplay on the screen which has been tested support AHD 720P video.And we tested either interlaced or progressed bt1120 , it's the same result.


Here is what we do :

1. kernel version 4.1.15, we mamually applied the patch "L3.14.52_1.1.0_GA_bt656_output_patch"

2. uboot parameters:

         setenv displayinfo 'video=mxcfb0:dev=adv739x,BT1120-1080P30,if=BT1120,fbpix=RGB565 consoleblank=0\0'

         (dev=adv739x, we have changed the reg initial for PT1000 in the same device source code)

3. in the file "mxcfb_adv739x.c", add below code into adv739x_modedb[]:

/* 1080P30 Noninterlaced output */

"BT1120-1080P30", 30, 1920, 1080, 13468,//74.25M -->PT1120

41, 4,

0, 0,

280, 1,






"BT1120-720P60", 60, 1280, 720, 13468,

25, 5,

0, 0,

270, 1,





4. in the file"ipu_disp.c", changed the line " #define BT656_IF_DI_MSB 15"

change from 8 bits to 16 bits, and use io "DISP_DAT15 ~ DISP_DAT0"


5. in the file"clk-imx6q.c"

-imx_clk_set_parent(clk[IMX6QDL_CLK_IPU1_DI0_PRE_SEL], clk[IMX6QDL_CLK_PLL3_PFD1_540M]);

+   imx_clk_set_parent(clk[IMX6QDL_CLK_IPU1_DI1_PRE_SEL], clk[IMX6QDL_CLK_PLL5_VIDEO_DIV]);


After we have done these steps, we got this result:

We read the reg of PT1000, the line and column is not correct, 

for 1080P, it should be 1920*1080, but we got some wrong nunber as 1960*1088 from the regs, and it changes every time we read it.


We have tested the test pattern which generated by PT1000, it's OK and displayed come color block on the screen.

So we think maybe the problem is that the bt1120 signal of imx6 output is not compatible with the input signal of PT1000.


Here is out problems:

1. DO you have any new patches for bsp-L4.1.15 on BT1120 output?

2. For this changed line and column numbers problem, where would you locate the problem? Does it possible that the imx6 output clock is not correct?