On Wed, Oct 12, 2011 at 9:01 AM, Dave Airlie <airlied@xxxxxxxxx> wrote: >> But then we'd need a different set of accessors for every different >> drm/v4l/etc driver, wouldn't we? > > Not any more different than you need for this, you just have a new > interface that you request a sw object from, > then mmap that object, and underneath it knows who owns it in the kernel. oh, ok, so you are talking about a kernel level interface, rather than userspace.. but I guess in this case I don't quite see the difference. It amounts to which fd you call mmap (or ioctl[*]) on.. If you use the dmabuf fd directly then you don't have to pass around a 2nd fd. [*] there is nothing stopping defining some dmabuf ioctls (such as for synchronization).. although the thinking was to keep it simple for first version of dmabuf BR, -R > mmap just feels wrong in this API, which is a buffer sharing API not a > buffer mapping API. > >> I guess if sharing a buffer between multiple drm devices, there is >> nothing stopping you from having some NOT_DMABUF_MMAPABLE flag you >> pass when the buffer is allocated, then you don't have to support >> dmabuf->mmap(), and instead mmap via device and use some sort of >> DRM_CPU_PREP/FINI ioctls for synchronization.. > > Or we could make a generic CPU accessor that we don't have to worry about. > > Dave. > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>