Am 03.12.20 um 15:02 schrieb Thomas Zimmermann:
GEM VRAM helpers used to pin the BO in their implementation of vmap, so that they could not be relocated. In a recent discussion, [1] it became
Grrr, [1] was again supposed to point to the discussion at
https://patchwork.freedesktop.org/patch/400054/?series=83765&rev=1
clear that this is incorrect and that vmap should rather repend on the reservation lock to prevent relocation. This patchset addresses the issue.
Version 2 of the patchset is a significant rework. In particular, the helper function drm_gem_vram_vmap_unlocked() is gone and importers now acquire the reservation locks by themselves. I took Christian's A-bs only for patches that were not affected.
Patches 1 and 2 prepare the ast cursor code for the later changes.
Patch 3 pushes the BO locking into callers of vmap and vunmap. Besides the VRAM helpers, this affects ast, vboxvideo and the generic fbdev emulation.
Patches 4 to 6 clean up afterwards. BO pinning is not required any longer and the VRAM-internal helpers are not needed.
Patch 7 adds documentation to vmap and vunmap in struct dma_buf_ops. It hopefully reflects the discussion on the patchset's version 1.
Tested on ast with GEM VRAM and also on mgag200 to verify that the fbdev change does not interfere with GEM SHMEM.
v2:
- make importers acquire resv locks by themselves
- document dma-buf vamp/vunmap ops
Thomas Zimmermann (7): drm/ast: Don't pin cursor source BO explicitly during update drm/ast: Only map cursor BOs during updates drm/vram-helper: Move BO locking from vmap code into callers drm/vram-helper: Remove pinning from drm_gem_vram_{vmap,vunmap}() drm/vram-helper: Remove vmap reference counting drm/vram-helper: Simplify vmap implementation dma-buf: Write down some rules for vmap usage
Documentation/gpu/todo.rst | 15 +++++ drivers/gpu/drm/ast/ast_cursor.c | 70 +++++++++++++--------- drivers/gpu/drm/ast/ast_drv.h | 2 - drivers/gpu/drm/drm_client.c | 31 ++++++++++ drivers/gpu/drm/drm_fb_helper.c | 10 +++- drivers/gpu/drm/drm_gem_vram_helper.c | 85 ++++++--------------------- drivers/gpu/drm/vboxvideo/vbox_mode.c | 11 ++-- include/drm/drm_client.h | 2 + include/drm/drm_gem.h | 4 ++ include/drm/drm_gem_vram_helper.h | 17 +----- include/linux/dma-buf.h | 45 ++++++++++++++ 11 files changed, 175 insertions(+), 117 deletions(-)
-- 2.29.2