tearing effect in DGA
 

i have a program that uses DGA to render image from a sony skx1227 camera. the program is run on an amd gx2 processor with montavista linux as its OS. the problem is that video tearing occur when an object moves during video capturing. i'm trying to poll vga register 0x3da to capture the vertical sync event. my plan is that during vertical sync no image is rendered to the screen (no image is copied to the video framebuffer). is my method correct or are there any other better alternatives?