On Wed, Nov 28, 2012 at 6:13 PM, Jerome Glisse <j.glisse at gmail.com> wrote: > On Wed, Nov 28, 2012 at 5:18 PM, Thomas Hellstrom <thomas at shipmail.org> > wrote: >> On 11/28/2012 09:09 PM, Jerome Glisse wrote: >>> >>> On Wed, Nov 28, 2012 at 10:05 AM, <j.glisse at gmail.com> wrote: >>>> >>>> From: Jerome Glisse <jglisse at redhat.com> >>>> >>>> It make no sense to preserve caching state especialy when >>>> moving from vram to system. It burden the page allocator to >>>> match the vram caching (often WC) which just burn CPU cycle >>>> for no good reasons. >> >> >> Nack. >> This is a driver problem. >> >> What happens with this patch if you evict write-combined TT memory to >> system? >> That's why we want to preserve caching state in the first place. >> >> If you need a different behavior, you can fine-tune in driver::evict_flags, >> or in the >> radeon-case in radeon_move_ram_vram / radeon_move_vram_ram. > > No you can't. Because cur placement of vram will be wc, and thus it > will want to preserve it for gtt. Only way to force it is to declare > vram as cached too. > > Cheers, > Jerome
Now that i think a bit more to it, in all fairness you can do so from the driver side. Cheers, Jerome
