lvds 1440x900 Shake！

[liyu1]

Dear all !

     This video is the reaction of 1440x900 LVDS jitter

　　　　

　　　　http://www.56.com/u17/v_MTM1Mjg2NDU0.html

     Only 1440x900, the resolution will shake　！

　　　please help me !

　　　

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[igorpadykov]

Hi li

one can try sightly change ldb module frequencies

(for example decrease fps). Also it may be caused

signal reflections (too strong signals), for that change

cable length and check board layout.

Best regards

igor

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[liyu1]

    static struct fb_videomode ldb_modedb[] = {

         "LDB-1440P60", 60, 1440, 900, 9259,

          240,10,//148, 88,

          69, 10,

          30, 8,

          0

          FB_VMODE_NONINTERLACED,

          FB_MODE_IS_DETAILED,},

    BOARD_KERNEL_CMDLINE := console=ttymxc0,115200 fb0base=0x27b00000 init=/init video=mxcfb0:dev=ldb,LDB-1440P60,if=RGB24,bpp=32 ldb=spl0 fbmem=28M video=mxcfb1:off video=mxcfb2:off vmalloc=450M androidboot.console=ttymxc0 androidboot.hardware=freescale

       android 4.4.2 normal　！　But Android 4.2.2 is not normal　！

[igorpadykov]

you can check Android 4.4.2 ldb clock settings

and make the same.

[liyu1]

1080P is ok !　The following settings：

BOARD_KERNEL_CMDLINE := console=ttymxc0,115200 fb0base=0x27b00000 init=/init 　　　video=mxcfb0:dev=ldb,LDB-1080P60,if=RGB24,bpp=32 ldb=spl0 fbmem=28M,28M video=mxcfb1:dev=hdmi,1920x1080M@60,bpp=32 video=mxcfb2:off vmalloc=450M androidboot.console=ttymxc0 androidboot.hardware=freescale

　

{

     "LDB-1080P60", 60, 1920, 1080, 6451,

     240,0,//148, 88,

     69, 0,

     30, 8,

0,//FB_SYNC_HOR_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT,

     FB_VMODE_NONINTERLACED,

     FB_MODE_IS_DETAILED,},

｝

everything is ok !

[igorpadykov]

suggest to look at

AN3974 Different Display Configurations on i.MX35 Linux PDK

how to add new resolution to BSP.

~igor

[liyu1]

You can test the 1440x900 resolution　？　I really got the problem !

[liyu1]

It is used by LVDS dual eight channel　！

[igorpadykov]

Freescale BSPs supports only LCDs used on

reference boards. For other LCDs one needs to add

support using AN3974.

[liyu1]

I suspect the reason resulted from the GPU.

[liyu1]

This is the screen parameters, I feel that the configuration is correct　！

　　

[liyu1]

I put the code to restore to the original state, also can appear such problem, I suspect that BSP does not support 1440x900 resolution　！

When I did 1080P,　android 4.2.2 everything is ok　！but 1440x 900 is not good !

　　　

[liyu1]

Are you sure the clock question　？

[liyu1]

Hi :

     But I use the same board, Android 4.4.2 will not appear such phenomenon !

[liyu1]

My client is waiting for the results, please help me to handle　！Thanks !