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Serious Flicking on 8"LCD when saving files through Samba or NFS

cwchang
Expert 1060 points

Dear All:

 

Recently we have a serious problem on DM355 when we save files through Samba or NFS.

Our system has a 8"LCD (800x600) with both video and OSD layers used.

There are a lot of flicking noises, when the system saves files through Samba or NFS.

I am wondering if it is caused by insufficient bus bandwidth.

Is there any solution to fix this problem?

Any suggestion will be appreciated.

 

Best regards,

 

Ray

 

  • 0
    TI__Mastermind 41665 points

    This does sound like it could be a bandwidth issue, the DM355 can run into a situation where the DDR bandwidth cannot keep up with the display, and as the real time dead line is broken, entire scan lines or portions of scan lines of video are lost. If you are seeing flickering horizontal lines on your LCD (something like this old thread), and it gets worse when you perform additional operations on the DM355 such as Samba/NFS accesses as you suggest, than the possibility of having a DDR bandwidth issue is high.

    As to fixing this, there is an article on the wiki at http://processors.wiki.ti.com/index.php/TMS320DM355_High-Definition_%28HD%29_Display which discusses ways of dealing with this problem, though it is focused on a 720p display example the same problems could crop up on an 800x600 display if the system is busy enough, and some of the fixes may still help. In particular you may want to try tweaking the PBBPR register if you have not already done so, and if possible reduce the regions in use by the video and OSD layers.