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DM8168 LCD

dal wheeler
Intellectual 610 points

connected a 1366x768 LCD panel to the DM8168, running 5.02 sdk. referencing:

http://processors.wiki.ti.com/index.php/DM816X_AM389X_VPSS_Video_Driver_User_Guide#Miscellaneous_Configurations

I'm trying to get the correct timing/VPSS to use the LCD.  I believe I'm correctly connected electrically as I'm getting a partial/ghosted image on the panel.

 

So far, I've routed /sys/devices/platform/vpss/graphics0/nodes to 1:dvo2, set display1/timings to various ~75mhz/front/back porch tries of 1366x768.  It seems that the VPSS unit is fixed to versions of 1280x720, as the bottom, and right sides of the LCD are blacked out.  Is this a hard-coded limitation of the current VPSS driver?

 

-Dal

  • 0
    TI__Mastermind 43875 points

    Dal,

    Can you send your panel specification and the settings you echoed to /sys/devices/platform/vpss/display1/timings ?

    BR,

    Steve

  • 0 in reply to Steve Clynes
    Intellectual 610 points

    75010,1366/50/107/30,768/7/25/5,1 and several similar combinations --I don't have front/back info, just the blanking periods of H=187, V=37.  I have two different make panels, one is DE mode only, both respond basically in the same way.

    Not sure if this is the correct way to address this --redirecting graphics0/nodes to the dv02.  Wanting to get a QT application to show up on the other port.

     

    Thanks!

    Dal

     

    From the LCD datasheet:

    Signal Item Symbol Min. Typ. Max. Unit Note

    DCLK Frequency     1/Tc 67.51 75.01 78.76 MHz  - 

    Vertical Total Time   TV   776   805   853   TH  - 

    Vertical Active Display Period   TVD   768   768   768 TH  - 

    Vertical Active Blanking Period  TVB   TV-TVD 37   TV-TVD   TH  - 

    Horizontal Total Time   TH   1405 1553 1600   Tc  - 

    Horizontal Active Display Period   THD   1366 1366 1366   Tc  - 

    DE 

    Horizontal Active Blanking Period   THB   TH-THD 187   TH-THD   Tc  -  

  • 0 in reply to dal wheeler
    Intellectual 610 points

    Weird, but I'm seeing the same behavior ghosting/720 line  behavior on HDMI if I ever send an echo 720p-60 >display0/mode; even if I send a 1080p-60 or adjust timings later.  Seems like the mode is sticking somehow.

    Is there a simple test I can do to set the timing mode, init fb1 and redirect QT to that framebuffer?

     

  • 0 in reply to dal wheeler
    Intellectual 610 points

    Got it!

    it was an old fbset that I didn't change

    fbset -xres 1366 -yres 768 -vxres 1366 -vyres 768

    fbset -depth 32 -rgba 8/16,8/8,8/0,0/0

    fixed it...

     

    Thanks!

     

  • 0 in reply to dal wheeler
    TI__Mastermind 43875 points

    Dal,

    Glad you are now working correclty.

    BR,

    Steve

  • 0 in reply to Steve Clynes
    TI__Mastermind 20245 points

    Hi,

    Since we are changing the timing parameters through sysfs and not through fbdev, its always required to do fbset once you change timing parameters. sysfs is used because both V4L2 and fbdev may requried timing parameter changing.

     

    Regards,

    Hardik Shah