On Wed, Nov 13, 2019 at 2:18 AM Daniel Vetter <daniel@xxxxxxxx> wrote: > > On Wed, Nov 13, 2019 at 8:39 AM Gerd Hoffmann <kraxel@xxxxxxxxxx> wrote: > > > > Hi, > > > > > > > >> VRAM helpers use drm_gem_ttm_mmap(), which wraps ttm_bo_mmap_obj(). > > > > > >> These changes should be transparent. > > > > > > > > > > > > There's still the issue that for dma-buf mmap vs drm mmap you use > > > > > > different f_mapping, which means ttm's pte shootdown won't work correctly > > > > > > for dma-buf mmaps. But yeah normal operation for ttm/vram helpers should > > > > > > be fine. > > > > > > > > > > VRAM helpers don't support dmabufs. > > > > > > > > It's not that simple. Even when not supporting dma-buf export and > > > > import it is still possible to create dma-bufs, import them into the > > > > same driver (which doesn't actually export+import but just grabs a gem > > > > object reference instead) and also to mmap them via prime/dma-buf code > > > > path ... > > > > ... but after looking again I think we are all green here. Given that > > only self-import works we'll only see vram gem objects in the mmap code > > path, which should have everything set up correctly. Same goes for qxl. > > > > All other ttm drivers still use the old mmap code path, so all green > > there too I think. Also I somehow doubt dma-buf mmap vs. drm mmap ends > > up using different f_mapping, ttm code has a WARN_ON in ttm_bo_vm_open() > > which would fire should that be the case. > > > > Do imported dma-bufs hit the drm mmap code path in the first place? > > Wouldn't mmap be handled by the exporting driver? > > drm_gem_dmabuf_mmap -> obj->funcs->mmap -> ttm_bo_mmap_obj > > And I'm not seeing anyone adjusting vm_file->f_mapping anywhere here at all. > > Note to hit this you need userspace to > - handle2fd on a buffer to create a dma-buf fd > - call mmap directly on that dma-buf fd That was exactly the vgem IGT test that prompted $subject fix. (With vgem modified to use shmem helpers) Rob _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
