On Fri, Oct 05, 2012 at 09:37:59PM +0200, Marcin Slusarz wrote: > It's questionable use case, but weston/wayland already relies on this > behaviour,
Important detail: weston does it only once per session. > and other drivers don't care about it, so it's a matter of compatibility. I looked into weston sources and produced a patch, but it's quite ugly. > 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