On 05-12-2017 11:53, Alexey Brodkin wrote: > > From my note above about udl_drm_gem_mmap() being only used in case of Xserver > I barely may conclude anything. Given my lack of knowledge of DRM guts > especially > when it comes to complicated cases with DMA buffer exports/imports I cannot say > immediately if that's just improper implementation of > udl_drm_gem_mmap() or not. > Even though I do see some differences between implementation of file_operations->mmap() > callback in UDL and > say exynos_drm_gem_mmap() or qxl_mmap() it's not clear > why this and that implementation was done. Oh, I've seen this before. This is the same thing that arcpgu used to do in the mmap callback! Please comment out the call to update_vm_cache_attr() in the mmap callback and check if it works.
