On Mon, Jul 17, 2017 at 11:39:56AM +0200, Maarten Lankhorst wrote: > Op 15-07-17 om 11:31 schreef Daniel Vetter: > > The legacy plane->fb pointer is refcounted by calling > > drm_atomic_clean_old_fb(). > > > > In practice this isn't a real problem because: > > - The caller in the i915 gpu reset code restores the original state > > again, which means the plane->fb pointer won't change, hence can't > > leak. > > - Drivers using drm_atomic_helper_shutdown call the fbdev cleanup > > first, and that usually cleans up the fb through > > drm_remove_framebuffer, which does this correctly. > > - Without fbdev the only framebuffers are from userspace, and those > > get cleaned up (again using drm_remove_framebuffer) befor the driver > > can even be unloaded. > > > > But in i915 I've switched the cleanup sequence around so that the > > _shutdown() calls happens after the drm_remove_framebuffer(), which is > > how I discovered this issue. > > > > v2: My analysis why the current code was ok for gpu reset and > > suspend/resume was correct, but then I totally failed to realize that > > we better keep this symmetric. Thanksfully CI noticed that for > > balance, a refcounting bug must exist at 2 places if previously there > > was no issue ... > > > > v3: Don't be lazy and compute the plane_mask in > > commit_duplicated_state properly too, instead of just using ~0U. > > > > Cc: martin.pe...@free.fr > > Cc: ch...@chris-wilson.co.uk > > Acked-by: Dave Airlie <airl...@gmail.com> (v1) > > Signed-off-by: Daniel Vetter <daniel.vet...@intel.com> > > --- > > drivers/gpu/drm/drm_atomic_helper.c | 18 ++++++++++++++++-- > > 1 file changed, 16 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c > > b/drivers/gpu/drm/drm_atomic_helper.c > > index b07fc30372d3..545328a9a769 100644 > > --- a/drivers/gpu/drm/drm_atomic_helper.c > > +++ b/drivers/gpu/drm/drm_atomic_helper.c > > @@ -2726,6 +2726,7 @@ int drm_atomic_helper_disable_all(struct drm_device > > *dev, > > struct drm_plane *plane; > > struct drm_crtc_state *crtc_state; > > struct drm_crtc *crtc; > > + unsigned plane_mask = 0; > > int ret, i; > > > > state = drm_atomic_state_alloc(dev); > > @@ -2768,10 +2769,14 @@ int drm_atomic_helper_disable_all(struct drm_device > > *dev, > > goto free; > > > > drm_atomic_set_fb_for_plane(plane_state, NULL); > > + plane_mask |= BIT(drm_plane_index(plane)); > > + plane->old_fb = plane->fb; > > } > > > > ret = drm_atomic_commit(state); > > free: > > + if (plane_mask) > > + drm_atomic_clean_old_fb(dev, plane_mask, ret); > > drm_atomic_state_put(state); > > return ret; > > } > > @@ -2902,11 +2907,16 @@ int > > drm_atomic_helper_commit_duplicated_state(struct drm_atomic_state *state, > > struct drm_connector_state *new_conn_state; > > struct drm_crtc *crtc; > > struct drm_crtc_state *new_crtc_state; > > + unsigned plane_mask = 0; > > + struct drm_device *dev = state->dev; > > + int ret; > > > > state->acquire_ctx = ctx; > > > > - for_each_new_plane_in_state(state, plane, new_plane_state, i) > > + for_each_new_plane_in_state(state, plane, new_plane_state, i) { > > + plane_mask |= BIT(drm_plane_index(plane)); > We should really add a drm_plane_mask/drm_connector_mask at some point, to > complement drm_crtc_mask. > > state->planes[i].old_state = plane->state; > > + } > > > > for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) > > state->crtcs[i].old_state = crtc->state; > > @@ -2914,7 +2924,11 @@ int drm_atomic_helper_commit_duplicated_state(struct > > drm_atomic_state *state, > > for_each_new_connector_in_state(state, connector, new_conn_state, i) > > state->connectors[i].old_state = connector->state; > > > > - return drm_atomic_commit(state); > > + ret = drm_atomic_commit(state); > > + if (plane_mask) > > + drm_atomic_clean_old_fb(dev, plane_mask, ret); > Kill the if () part, and make it unconditional? On second thought, I should > have done the same in drm_framebuffer.c
I'd prefer to not bikeshed this stuff too much and just go with what we do everywhere else (i.e. rmfb code and atomic commit) for consistency. clean_old_fb is definitely a horrible function with misleading kerneldoc on top, and I think the best way to clean that up would be to: - Move the plane_mask computation in drm_atmic_commit and also put the clean_old_fb call in there. Maybe give it a more descriptive name like update_legacy_fb or whatever. Unexport them. - This would break the compat helpers, where drm_atomic_commit must not update the legacy refcounts, because for set_config, page_flip and the plane hooks the core does that already. Create a drm_atomic_commit_legacy for these. But since one of my patches caused an existing issue to pop up as a regression, and this series fixes it, I'd like to first get the minimal fix in through drm-intel. And then bikeshed it properly in drm-misc. Typing the patches is also a bit annoying right now since I have a few other atomic_commit patches in-flight ... Thanks, Daniel > > + return ret; > > } > > EXPORT_SYMBOL(drm_atomic_helper_commit_duplicated_state); > > > > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel