On Monday 03 December 2001 03:45 am, you wrote: > On Sun, 2 Dec 2001, Mark Vojkovich wrote: > > > On Sun, 2 Dec 2001, Billy Biggs wrote: > > > > > > Why does it take so long to copy the data to the framebuffer? Can't > > > we use DMA here? Does it really take that long to just copy 512k? > > > > It's a little more than that because the driver is using > > 4:2:2 internally. Copying the way it is doing you can't get > > much more than 160 MB/sec and uses the CPU the whole time. > > DMA won't make the transfer go any faster (it will probably > > be slower unless you're using 2x+ AGP), but it won't eat the > > CPU. The only drivers that do this are NVIDIA's binary > > drivers and supposedly some experimental ATI drivers that > > some people are working on. Maybe the i810 drivers do too, > > not that it would help, since the bandwidth is probably the > > same writing to video ram or the framebuffer. > > I thought the DMA'ified ATI-drivers were in the xfree86 CVS-tree by now? > More or less on-topic links below. > http://www.linuxvideo.org/lists/livid-gatos/2001-September/msg00007.html > http://www.mail-archive.com/dri-devel@lists.sourceforge.net/msg01368.html > http://www.xfree86.org/pipermail/xpert/2001-September/011481.html > > On another issue: > Billy, check out the syncfb driver in the teletux project at sf. > The CVS version is in active development. It gives way better performance > than Xv on matrox cards, even though it is still mmio (AFAICT, which > doesn't tell a lot). > > "Syncfb is a kernel module that synchronizes the output > of video frames with the monitor frequency to avoid > vertical artifacts (tearing) in the picture. > > This is done by creating a FIFO buffer inside the > video ram of the graphics card and switching from > one buffer to the next on vertical blanking interrupt. > > Syncfb also provides support for other video > related hardware accelerations like scaling, hardware > de-interlacing (usually only bi-linear interpolation of > fields) and YUV->RGB conversion if available." > That may work, but it's not very portable... What about all of us who use FreeBSD.
Ken _______________________________________________ Xpert mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/xpert
