On Mon, Aug 12, 2024 at 01:51:30PM +0200, Andi Shyti wrote: > Hi Daniel, > > On Mon, Aug 12, 2024 at 11:11:21AM +0200, Daniel Vetter wrote: > > On Fri, Aug 09, 2024 at 11:20:56AM +0100, Andi Shyti wrote: > > > On Fri, Aug 09, 2024 at 10:53:38AM +0200, Daniel Vetter wrote: > > > > On Wed, Aug 07, 2024 at 11:05:19AM +0100, Andi Shyti wrote: > > > > > This patch series concludes on the memory mapping fixes and > > > > > improvements by allowing partial memory mapping for the cpu > > > > > memory as well. > > > > > > > > > > The partial memory mapping by adding an object offset was > > > > > implicitely included in commit 8bdd9ef7e9b1 ("drm/i915/gem: Fix > > > > > Virtual Memory mapping boundaries calculation") for the gtt > > > > > memory. > > > > > > > > Does userspace actually care? Do we have a flag or something, so that > > > > userspace can discover this? > > > > > > > > Adding complexity of any kind is absolute no-go, unless there's a > > > > userspace need. This also includes the gtt accidental fix. > > > > > > Actually this missing functionality was initially filed as a bug > > > by mesa folks. So that this patch was requested by them (Lionel > > > is Cc'ed). > > > > > > The tests cases that have been sent previously and I'm going to > > > send again, are directly taken from mesa use cases. > > > > Please add the relevant mesa MR to this patch then, and some relevant > > explanations for how userspace detects this all and decides to use it. > > AFAIK, there is no Mesa MR. We are adding a feature that was > missing, but Mesa already supported it (indeed, Nimroy suggested > adding the Fixes tag for this). > > Also because, Mesa was receiving an invalid address error and > asked to support the partial mapping of the memory. Uh this sounds a bit too much like just yolo'ing uabi. There's two cases: - Either this is a regression, it worked previously, mesa is now angry. Then we absolutely need a Fixes: tag, and we also need that for the preceeding work to re-enable this for gtt mappings. - Or mesa is just plain wrong here, which is what my guess is. Because bo mappings have always been full-object (except for the old-style shm mmaps). In that case mesa needs to be fixed (because we're not going to backport old uapi). Also in that case, _if_ (and that's a really big if) we really want this uapi, we need it in xe too, it needs a proper mesa MR to use it, it needs igt testcases, and it needs a solid way to detect whether the kernel supports this feature or not. But unless other drivers are doing this too, I have some big questions why i915-gem needs this. > > Also, does xe also support this? If we only add this to i915-gem but xe > > doesn't have it, it doesn't make much sense imo. > > I don't know about. Lionel, Do you have anything to add here from > your side? "I don't know" is not an acceptable answer for uapi work. -Sima -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch