On Mon, Feb 19, 2007 at 11:13:04PM -0500, Jaya Kumar wrote: > On 2/18/07, Paul Mundt <[EMAIL PROTECTED]> wrote: > >Given that, this would have to be something that's dealt with at the > >subsystem level rather than in individual drivers, hence the desire to > >see something like this more generically visible. > > > > Hi Peter, Paul, fbdev folk, > > Ok. Here's what I'm thinking for abstracting this: > > fbdev drivers would setup fb_mmap with their own_mmap as usual. In > own_mmap, they would do what they normally do and setup a vm_ops. They > are free to have their own nopage handler but would set the > page_mkwrite handler to be fbdev_deferred_io_mkwrite().
The vast majority of drivers do not implement ->fb_mmap(), and with proper abstraction, this should be something that's possible as a direct alternative to drivers/video/fbmem.c:fb_mmap() for the people that want it. Of course it's just as easy to do something like the sbuslib.c route and then have drivers set their ->fb_mmap() from that too. > fbdev_deferred_io_mkwrite would build up the list of touched pages and > pass it to a delayed workqueue which would then mkclean on each page > and then pass a copy of that page list down to a driver's callback > function. The fbdev driver's callback function can then do the actual > IO to the framebuffer or coalesce DMA based on the provided page list. > That works for me, though I'd prefer for struct page_list to be done with a scatterlist, then it's trivial to setup from the workqueue context without having to shuffle things around. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/