Behavior of drmModeSetCrtc wrt to framebuffer

Hi All,

I need your help in determining the behavior of drmModeSetCrtc when it is called with a FB and mode. Should it display the content of FB to physical screen or not?

I ran the program https://github.com/dvdhrm/docs/blob/master/drm-howto/modeset.c with Vmware's vmwgfx drm driver and it will not display the FB, but calling drmModeDirtyFB after the FB has modified, the program works as expected (to display the fb content to screen). Also the same program works as expected with intel drm driver.

Please let me know if you need any other information.

Thanks in advance, Deepak