SDL game testing using Dolphin problem [black screen]

[geryright]

Hi
I want to test my SDL game in Dolphin emulator.
I compile everything succesfully but when I tried to run it in Dolphin emu I can't see anything

Only black screen is shown...

I made several "debug" poiints with printf() so if you run .elf in Dolphin you can see messages like "InitSOundSystem OK!"
"load_image("data.bmp") OK "and everything is fine

But nothing is shown at the screen (code calls SDL_Blit() etc several times)

I made this game for Linux and PC-Win also and there it works fine, but in Dolphin nothing is shown

What should I do?