It's questionable use case, but weston/wayland already relies on this behaviour, and other drivers don't care about it, so it's a matter of compatibility. Without it, process invoking such page flip hangs in unkillable state, trying to reserve the same buffer twice.
Signed-off-by: Marcin Slusarz <marcin.slus...@gmail.com> --- drivers/gpu/drm/nouveau/nouveau_display.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/nouveau/nouveau_display.c b/drivers/gpu/drm/nouveau/nouveau_display.c index 61f370d..a52cfd3 100644 --- a/drivers/gpu/drm/nouveau/nouveau_display.c +++ b/drivers/gpu/drm/nouveau/nouveau_display.c @@ -530,9 +530,11 @@ nouveau_page_flip_reserve(struct nouveau_bo *old_bo, if (ret) goto fail; - ret = ttm_bo_reserve(&old_bo->bo, false, false, false, 0); - if (ret) - goto fail_unreserve; + if (likely(old_bo != new_bo)) { + ret = ttm_bo_reserve(&old_bo->bo, false, false, false, 0); + if (ret) + goto fail_unreserve; + } return 0; @@ -551,8 +553,10 @@ nouveau_page_flip_unreserve(struct nouveau_bo *old_bo, nouveau_bo_fence(new_bo, fence); ttm_bo_unreserve(&new_bo->bo); - nouveau_bo_fence(old_bo, fence); - ttm_bo_unreserve(&old_bo->bo); + if (likely(old_bo != new_bo)) { + nouveau_bo_fence(old_bo, fence); + ttm_bo_unreserve(&old_bo->bo); + } nouveau_bo_unpin(old_bo); } @@ -624,6 +628,12 @@ nouveau_crtc_page_flip(struct drm_crtc *crtc, struct drm_framebuffer *fb, if (!drm->channel) return -ENODEV; + if (unlikely(old_bo == new_bo)) { + char name[sizeof(current->comm)]; + pr_debug_ratelimited("'%s': useless page flip invoked\n", + get_task_comm(name, current)); + } + s = kzalloc(sizeof(*s), GFP_KERNEL); if (!s) return -ENOMEM; -- 1.7.12 _______________________________________________ Nouveau mailing list Nouveau@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/nouveau