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DVRRDK VGA output flicker problem

The platform I am using is DVRRDK 4.0 on dm8168

For output display, I have tied HDMI and HDCOMP so I can get video for both HDMI and VGA.

and I face the problem as in   last post in 

 http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/717/t/236635.aspx?pi199607=2

on VGA output, the whole screen shift a bit and a black bar is seen. And more important is that the output is flicker. But everything on HDMI output is completely fine.

The VGA output shows video properly for some time, like several ten seconds. And then it would flash once. The whole screen gets black. But it get back to normal after 1 or 2 second. It keeps happening repeatly. 

However, there is some strange points. On some VGA monitors, it does not have this problem. While on some monitors it has. And sometimes ago we test monitor A not having problem, but now it does.

Another point is that if I don't tie HDMI and HDCOMP together, so it ties HDCOMP and DVO2 by default. I tried using VGA output and there is no screen shift and screen flicker problem.

please help, thanks.

  • After some testings, I find the screen flash problem occur after I set the display resolution through Vdis_setResolution(). THe code is given below.

    Vdis_sysfsCmd(3, VDIS_SYSFSCMD_SET_GRPX, VDIS_SYSFS_GRPX0, VDIS_OFF);
    Vdis_sysfsCmd(3, VDIS_SYSFSCMD_SET_GRPX, VDIS_SYSFS_GRPX1, VDIS_OFF);
    Vdis_sysfsCmd(3, VDIS_SYSFSCMD_SET_GRPX, VDIS_SYSFS_GRPX2, VDIS_OFF);

    Vdis_stopDrv(_this->disp_dev);

    Vdis_setResolution(_this->disp_dev, _this->vid_std);

    _DISP_LINK_change_screen_mode(_this);

    Vdis_startDrv(_this->disp_dev);

    Vdis_sysfsCmd(3, VDIS_SYSFSCMD_SET_GRPX, VDIS_SYSFS_GRPX0, VDIS_ON);
    Vdis_sysfsCmd(3, VDIS_SYSFSCMD_SET_GRPX, VDIS_SYSFS_GRPX1, VDIS_ON);
    Vdis_sysfsCmd(3, VDIS_SYSFSCMD_SET_GRPX, VDIS_SYSFS_GRPX2, VDIS_ON);

    where _this->disp_dev = VDIS_DEV_HDMI as I tie HDMI and HDCOMP.

    Is there any idea why is the flash happening on some VGA monitors after this?

    Thanks

  • any help please? 

    Thanks

  • Any idea please?