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i.MX6: gpu API glTexDirectVIVMap HSYNC abnormal

Question asked by lin ya on Apr 14, 2017
Latest reply on May 5, 2017 by Bio_TICFSL

I update texture by glTexDirectVIVMap, there may be tearing on screen.
I check the message from


I test kernel version 3.14.28 and 3.14.52 with different number of FB-buffers.
bellow are my test result:

kernel=3.14.28 FB_MULTI_BUFFER=1 HSYNC abnormal
kernel=3.14.28 FB_MULTI_BUFFER=2 HSYNC ok
kernel=3.14.28 FB_MULTI_BUFFER=3 HSYNC ok


kernel=3.14.52 FB_MULTI_BUFFER=1 HSYNC abnormal
kernel=3.14.52 FB_MULTI_BUFFER=2 HSYNC abnormal
kernel=3.14.52 FB_MULTI_BUFFER=3 HSYNC ok


It's seems the GPU performance is turn to bad while upgrade it's version to

The question is : Why the new GPU version need one more buffer to solve the HSYNC problem?
One more buffer mean bad frame delay.
How to solve this problem with FB_MULTI_BUFFER=2 on new GPU version?