On 2/24/07, Antonino A. Daplas <firstname.lastname@example.org> wrote:
We could. But I think fb_deferred_io_vm_nopage would then have to
handle the different types or possible combinations of framebuffer
allocations, if they kmalloced or vmalloced or maybe combinations. Ok.
I'll try to implement that. Maybe we'll need a flag where the driver
informs us of the type of allocation.
I agree it'll be much cleaner that way but was worried if having
fb_defio do that would prevent driver writers from having their own
nopage and controlling other vm related functionality. Looking at
drivers/video/* shows no one touching vm_ops, so I guess we'll be
fine. If fb_defio takes ownership of the driver's nopage, vm_ops, etc,
then it could be just the above struct and the
fb_deferred_io_init/cleanup functions that are exposed to the driver.
ie: if an fbdev driver calls fb_deferred_io_init, we setup their mmap,
vm_ops and the necessary bits. I'll give that a shot.
Understood. I had done it that way originally but changed just before
posting. I'll revert back. :)
Yup, hecuba doesn't have clean partial update functionality. But the
callback exposed to drivers is:
+ void (*deferred_io)(struct fb_info *info, struct list_head *pagelist);
which gives the drivers the list of dirty pages in pagelist. So other
drivers for hardware with the right capabilities can implement
selective or partial updates. As you mentioned, I imagine that the
drivers internally could have a bit array to enable them to mark and
find sequential partial updates. I would leave the page bitmap for
drivers to do since it would be specific to their hardware.