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Re: Xfree86 video buffering?
From: bkfsec <bkfsec () sdf lonestar org>
Date: Fri, 25 Feb 2005 10:49:02 -0500

Valdis.Kletnieks () vt edu wrote:

I don't think this is at all easily solvable - when the X server starts up, the
card is probably in console mode using the VGA emulation, which is pretty
brain-dead and doesn't touch much of the card memory (when you have 32M or 64M
on-card, that 640x480 gets lonely sitting in the corner).  The X server first
has to pop it into the native NVidia/ATI/whatever graphics mode (remember, it
has to do that *before* it can access the video memory - you can't get there
while still in VGA emulation).  Then it can proceed to clear out the on-card
memory.  Unfortunately, if the X server pauses in between setting the mode and
clearing  the memory, you get to see the uninitialized (and therefor left-over)
buffers.  About the best you can do here is fix the server to try to not do any
time-intensive operations between the mode set and the clear.

Just a thought here... don't know if there are any complications with my suggestion here, but -- why not go the other route and clear the video memory as X is shutting down, such that there's no stale data left in the buffers?

         -Barry


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