[visionegg] Re: latest xfree86: sync buffer swapping with ATI Radeon

Christoph Lehmann wrote:

Let us try to get the ync buffer swapping to vblank work... :)

xfree86.4.3,

which, according to Leif Delgas should make the synchronization of  the
swapping of OpenGL buffers with the vertical retrace signal, possible:

use 'export LIBGL_SYNC_REFRESH=t'."

I'm happy that the ATI Radeon drivers finally seem have support for such basic functionality in linux.

I added code to set this environment variable in December 2002. (See PlatformDependent.py) Therefore, You should not need to set the environment variable from the command-line.

I still get:


2003-04-29 09:26:54 (1287) info: OpenGL 1.2 Mesa 4.0.4, Mesa DRI Radeon
    20020611 AGP 1x x86/MMX/SSE TCL, Tungsten Graphics, Inc.
2003-04-29 09:26:54 (1287) info: Video system reports 32 bpp (8 8 8 8
RGBA).
2003-04-29 09:26:54 (1287) WARNING: Could not sync buffer swapping to
vblank
    because you are running linux but not known/supported drivers (only
    nVidia and recent Mesa DRI Radeon currently supported).

Yes, that's just a warning because there's no way for the Vision Egg to verify that it actually worked. There's a check to make sure your drivers were labeled as coming after 20021216, but your are only from 20020611. I'm not sure when the functionality was added, but you might be OK.

The way to find out is to look at the histogram of your frame timing statistics. When drawing simple stimuli does your frame rate drop dramatically to the vertical refresh rate of your monitor? If so, it works. If not, you may want to try getting the latest ATI drivers or otherwise ensuring that this environment variable works.

Cheers!
Andrew

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