Tearing in OpenGL

[Balazs1z]

Hello,

I am playing with OpenGL on a custom i.MX515 board. Unforunatelly i can observe some tearing while im running the OpenGL demos or my software. Also when i start my program a warning message is displayed:

Color formats don't match.  Falling back to copy forward swap.

My framebuffer color depth is 16 bit as reported by the kernel and the display config is requested as 5/6/5/0 in OpenGL.

Have any of you seen this problem? Where should i fix the color format?

I assume this should fix my problem with the tearing.

Many thanks in advance for any help,

Balazs

[Balazs1z]

Hi Brian, Yep that was the problem. Fixed the issue by setting the framebuffer to 32bit and requesting a 8/8/8/8 config. Thanks, Balazs

[smspatrick]

Hi Balazs,

I'm having the same issue, but absolute need the 8888 setup. Can you tell please how you set the frambuffer bpp? At Runtime via ioctl or during system boot in device register? It seems that my fb-dev is big enough (>33M (from fixed-info smem) @ 1024*720*32bpp) so reset the bpp info should be possible.

thanks

[BrianMurray]

Make sure you are getting back a 565 config as setting those as a minimum in the config struct doesn't necessarily mean you are getting it (e.g. the first config returned could be 888).  Also, it could be failing swap if the virtual size of the famebuffer isn't big enough for triple buffering.  Try using fbset to increase the vertical size to 4x the frame size (3x for triple buffering and some extra to account for alignment).  

-Brian