I am using SabreSD evaluation kit with Linux BSP ltib-4.1.1, I have cross-compiled Qt5 and running its test applications with success. From documentation I read that the following environment variable can affect both vertical synch and number of framebuffers used:
- FB_MULTI_BUFFER=1, then one framebuffer is used and vsync is disabled
- FB_MULTI_BUFFER=2, then 2 framebuffers are used and vsync is enabled
My LCD is 1024x600@60Hz and framebuffer virtual size is 1024x600 16bpp.
I have two questions:
- in case FB_MULTI_BUFFER=2, I do not see any change in virtual size, it is always 1024x600. Is it correct? I expected fb driver to be asked for twice as vxres or vyres;
- in case FB_MULTI_BUFFER=1, is there any way to enable vsync anyway? I ask that because my specific application requires framebuffer grabbing, so one framebuffer is a requirement.
Thanks for help.