Hi Bernd. Considering FBdev. flipping from backbuffer to frontbuffer is done via 'panning'. The reserved FB area is, in case of double buffering, simply doubled by doubling the y-coordinate, check out dfb_fbdev_mode_to_var() in fbdev.c and look for yres_virtual. So, it is possible to offload surface memory to pools as Daniel points out, but spreading your front/back buffers across multiple pools is not possible with the current FBdev implementation, as far as I can tell.
hth Niels Weber, Bernd wrote: > > Thanks! > > I think I finally figured it out. I think there wasn’t actually 20MB > available in the framebuffer memory but only the 8MB of visible > framebuffer. Anyway, this leads me to the following question: > > Is there a way to specify 2 separate memory regions that are used by > DirectFB, one as the actual framebuffer through the /dev/fb – > framebuffer device and then a second area that is used as backbuffer > etc? Meaning a non contiguous memory! I didn’t see anything that would > allow me to do something like that but I might be wrong and overlooked > something. > > -Bernd > > ------------------------------------------------------------------------ > > *From:* Amarinder Singh Sethi [mailto:[EMAIL PROTECTED] > *Sent:* Thursday, October 30, 2008 11:55 PM > *To:* Weber, Bernd > *Subject:* Re: [directfb-dev] Writing a gfxdriver > > I would recommend reading the DirectFB tutorial for understanding the > basic concepts such as screen and layers. Regarding the memory > mapping, the video memory (frame buffer) of your graphics card should > be mapped in user space when using fbdev system. This mapping should > include both the front and back buffers provided your hardware has > enough memory available for supporting double buffering. > > -Amarinder > > ------------------------------------------------------------------------ > _______________________________________________ > directfb-dev mailing list > directfb-dev@directfb.org > http://mail.directfb.org/cgi-bin/mailman/listinfo/directfb-dev > -- .------------------------------------------. | DirectFB - Hardware accelerated graphics | | http://www.directfb.org/ | "------------------------------------------" _______________________________________________ directfb-dev mailing list directfb-dev@directfb.org http://mail.directfb.org/cgi-bin/mailman/listinfo/directfb-dev
