VBO problems on ATI card

[gaoyakun]

I'm using ATI radeon 9200 SE.

When drawing primitives using GL_LINE(wireframe mode),glDrawElement call will crash. I runs fine when I simply comment out the glPolygonMode(GL_FRONT_AND_BACK, GL_LINE). The problem didn't occured on NV card. Would this be a Driver's BUG?

Another question:
Using VBO with GL_DYNAMIC_DRAW_ARB, I dynamically filled the buffer with several datas every frame, the FPS will going down from 500(using non-vbo vertex buffer) to 20. DevPartner tell me glUnmapBufferARB/glMapBufferARB taked too much time. Will this be problem in my code or display driver?

[gaoyakun]

I'v solved the second question. It is because i created several big vertex buffers at startup and each time the user query for a vertex array i allocate a chunk from the big buffers. But it is too slow to map/unmap a big buffer. Now for dynamic buffer, i will create a standalone buffer for it as small as possible. This solves the second problem.

Who can give me an idea about the first question?Thanks.

[Tom Nuydens]

If you suspect a driver bug, try e-mailing devrel@ati.com about it. Be sure to attach a small sample app that they can use to reproduce the problem.

-- Tom

[gaoyakun]

Thank'u, i have send an email to ATI. Hope it will be helpful.