X driver: Using offscreen memory manager for Xv

[Alex Deucher]

On Nov 26, 2007 8:08 PM, Bankim Bhavsar <bbhavsar at vmware.com> wrote:
> I'm implementing Xv extension of linux X driver.
>
> I need to use offscreen memory to allocate space for incoming video-frames.
> Currently, I am using xf86InitFBManager() part of xf86fbman.h to
> initialize offscreen memory by specifying a BoxPtr. The offscreen
> memory is initialized such that it starts just after the on-screen
> memory (using Frame Buffer Size).
>
>
> When there is a ModeSwitch the Frame Buffer Size changes and the
> offscreen memory previously allocated becomes a part of the on-screen
> memory and causes X to crash. I was thinking of re-initalizing the
> Offscreen memory manager on ModeSwitch and modify the previously
> allocated pointers accordingly but I don't see a way to re-initialize
> the offscreen memory.
>
>
> One possible solution would be to leave some space before starting the
> offscreen memory. That would work for common case but still doesn't
> guarantee the framebuffer extending into the previously initialized
> offscreen memory.
>
>
> I also looked into EXA but doesn't seem to serve the purpose either.
>
>
> Am I missing out on something? Any other possible solution?
> Can someone point me to a driver that uses EXA and handles the offscreen
> memory on ModeSwitch?

I believe nv does this.

Alex