I am trying to emulate a board which has a OLED display, but can't see anything. Can you tell me if there is something important I am not considering?

I am just a newbie that is trying to learn. I can't see anything in the OLED display (ssd0303).

I am just using this demo: https://www.freertos.org/portlm3s811keil.html

as you can see it says that:

The print task is the only task permitted to access the LCD - thus ensuring mutual exclusion and consistent access to the resource. Other tasks do not access the LCD directly, but instead send the text they wish to display to the print task. The print task spends most of its time blocked - only waking when a message is queued for display.

but actually, if I compile using make and running using qemu-system-arm -M lm3s811evb -kernel gcc/RTOSDemo.bin I can only see that black screen.

Why? Is there something I am not considering? It should work out of the box, since it's also writen in the official doc that I mentioned. So why I see black screen?

Probably there is something I am not considering because I am a newbie

I fixed by compiling via Keil instead of gcc: https://forums.freertos.org/t/i-am-trying-to-emulate-a-board-which-has-a-oled-display-but-cant-see-anything-can-you-tell-me-if-there-is-something-important-i-am-not-considering/18689/3