For virtual framebuffers that need to shuffle pixels over a bus or network, to be efficient they need to get notification of what pixels are changing in the case of a memory mapped framebuffer. This has come up before (Jaya/others have thought and talked about this), and here's another example implementation (for DisplayLink USB devices): http://plugable.com/2010/05/21/linux-support-for-higher-res-monitors-on-lower-res-displaylink-devices/ This uses a hacked ioctl. But there's a commented out proposal in there for cleaning it up. It would be great to standardize the interface for passing damage notifications (from X or other) down to kernel. Some open questions: * Which ioctl ordinal could be reserved for this (maybe 'F' 0x1A?) * What struct (just a single rect as above, or pass X damage struct down directly?) * User-configured (with X option as with implementation above), or auto-negotiated between kernel and user? Any thoughts or comments on this, and the feasibility of eventually getting this into fbdev (and xf86-video-fbdev) are welcome. Best wishes, Bernie http://plugable.com/ -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
