On Fri, Dec 11, 2015 at 12:29:40PM +0000, Chris Wilson wrote: > On Fri, Dec 11, 2015 at 12:19:09PM +0000, Dave Gordon wrote: > > On 10/12/15 08:58, Daniel Vetter wrote: > > >On Mon, Dec 07, 2015 at 12:51:49PM +0000, Dave Gordon wrote: > > >>I think I missed i915_gem_phys_pwrite(). > > >> > > >>i915_gem_gtt_pwrite_fast() marks the object dirty for most cases (vit > > >>set_to_gtt_domain(), but isn't called for all cases (or can return before > > >>the set_domain). Then we try i915_gem_shmem_pwrite() for non-phys > > >>objects (no check for stolen!) and that already marks the object dirty > > >>[aside: we might be able to change that to page-by-page?], but > > >>i915_gem_phys_pwrite() doesn't mark the object dirty, so we might lose > > >>updates there? > > >> > > >>Or maybe we should move the marking up into i915_gem_pwrite_ioctl() instead. > > >>The target object is surely going to be dirtied, whatever type it is. > > > > > >phys objects are special, and when binding we create allocate new > > >(contiguous) storage. In put_pages_phys that gets copied back and pages > > >marked as dirty. While a phys object is pinned it's a kernel bug to look > > >at the shmem pages and a userspace bug to touch the cpu mmap (since that > > >data will simply be overwritten whenever the kernel feels like). > > > > > >phys objects are only used for cursors on old crap though, so ok if we > > >don't streamline this fairly quirky old ABI. > > >-Daniel > > > > So is pread broken already for 'phys' ? > > Yes. A completely unused corner of the API. I think it would be useful to extract all the phys object stuff into i915_gem_phys_obj.c, add minimal kerneldoc for the functions, and then an overview section which explains in detail how fucked up this little bit of ABI history lore is. I can do the overview section, but the extraction/basic kerneldoc will probably take a bit longer to get around to. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
