Hello everyone
Apologies if this is the wrong list to post in. Please point me in the correct direction if it is.
Lately I have been toying around with gbm + dri, and I'm wondering how to support multiple desktops/screens properly. I had hoped that I could create one gbm surface that covers all screens and render to it (using egl in my case), after which I would lock the surface front buffer (gbm_lock_surface_front_buffer) and for each screen call drmModeAddFB and drmModeSetCrtc, providing appropriate (x,y) coordinates to drmModeSetCrtc according to the position. of the screen. Unfortunately, drmModeSetCrtc seems to fail every time (no space left on device) on my machine unless I provide (0,0) as the x and y coordinates. If I provide (0,0) as the coordinates I correctly get the top left corner of the buffer on each screen as expected.
Is this by design? If so, is it the expectation that one gbm surface is created separately for each screen? If so, are there any recommendation as to how to render one scene effectively across multiple screens?
Thanks in advance.