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VSync not really working on Axim X51v

Some time ago, when I started the development of my application, I remember having an issue with the Diamond. If I let the screen refresh as fast as possible, I experience a strange flickering on a random part of the screen. Never the whole screen, but a spot large enough to be annoying. After much time spent, I found out that adding a sleep(8) after the hardware page flip fixes the issue.  By the way, “8″ is the least amount of time spent to make the flickering disappear.

Does this mean that I can’t start drawing in my backbuffer straight after it has been flipped ? I should give some time to the hardware for the flipping, and then go ahead with my business ?

Since the diamond now uses hardware page flipping, I realized that it’s performance dropped (!) This is obviously due to the sleep(8). What if I remove it ?

6-7 fps improvement on the Diamond

8-9 fps improvement on the Axim, but flicker is back

Now, does this only happen on the Axim ? Maybe it’s a flaw in the hardware ? Or maybe it only concerns my own ROM.

And what would be the fix ? Should I assume that only the Axim is impacted, and I can put in a special case for it, or should I add some options to let the user tweak it himself ?

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