On Sun, Mar 13, 2005 at 11:04:59PM +1100, Benjamin Herrenschmidt wrote: > > > > I must be missing something something obvious because I don't quite > > understand what major drawbacks there are with the non-overlapping mode. > > As I see it you get at least the same amount of CPU accessible memory as > > you get in the overlapping mode. > > Yes, you do, but that means that if the apertures are configured such > that the entire VRAM fits in a single aperture, then you just can't use > the second aperture at all. Which means you can't have separate swapper > setting for both apertures, and thus, can't let two independant > processes access the video memory with different bit depth, at least on > big endian machines unless you do trickery, and play with the swapper > before each access.
Ok so the problem is byte swapping. Looking at atyfb for example it uses the "big-endian" aperture on big-endian systems and selects the byte swapping method according to the bit depth. If that really means that all host access to the aperture gets byte swapped then I don't see how the current situation can work correctly for DirectFB. Offscreen surfaces can use any bit depth and so their bytes could be swapped incorrectly. Makes me wish I had a PPC box alongside the x86 one. -- Ville Syrjälä [EMAIL PROTECTED] http://www.sci.fi/~syrjala/ ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_ide95&alloc_id396&op=click -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel