diff options
Diffstat (limited to 'target/linux/bcm27xx/patches-5.10/950-0681-drm-Introduce-an-atomic_commit_setup-function.patch')
| -rw-r--r-- | target/linux/bcm27xx/patches-5.10/950-0681-drm-Introduce-an-atomic_commit_setup-function.patch | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/target/linux/bcm27xx/patches-5.10/950-0681-drm-Introduce-an-atomic_commit_setup-function.patch b/target/linux/bcm27xx/patches-5.10/950-0681-drm-Introduce-an-atomic_commit_setup-function.patch new file mode 100644 index 0000000000..35b874ce71 --- /dev/null +++ b/target/linux/bcm27xx/patches-5.10/950-0681-drm-Introduce-an-atomic_commit_setup-function.patch @@ -0,0 +1,95 @@ +From 86fc6b59ae170399aaf8fd9880f1a3f79948f5a3 Mon Sep 17 00:00:00 2001 +From: Maxime Ripard <maxime@cerno.tech> +Date: Fri, 4 Dec 2020 16:11:32 +0100 +Subject: [PATCH] drm: Introduce an atomic_commit_setup function + +Private objects storing a state shared across all CRTCs need to be +carefully handled to avoid a use-after-free issue. + +The proper way to do this to track all the commits using that shared +state and wait for the previous commits to be done before going on with +the current one to avoid the reordering of commits that could occur. + +However, this commit setup needs to be done after +drm_atomic_helper_setup_commit(), because before the CRTC commit +structure hasn't been allocated before, and before the workqueue is +scheduled, because we would be potentially reordered already otherwise. + +That means that drivers currently have to roll their own +drm_atomic_helper_commit() function, even though it would be identical +if not for the commit setup. + +Let's introduce a hook to do so that would be called as part of +drm_atomic_helper_commit, allowing us to reuse the atomic helpers. + +Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch> +Signed-off-by: Maxime Ripard <maxime@cerno.tech> +--- + drivers/gpu/drm/drm_atomic_helper.c | 9 +++++++++ + include/drm/drm_modeset_helper_vtables.h | 21 +++++++++++++++++++++ + 2 files changed, 30 insertions(+) + +--- a/drivers/gpu/drm/drm_atomic_helper.c ++++ b/drivers/gpu/drm/drm_atomic_helper.c +@@ -2039,6 +2039,9 @@ crtc_or_fake_commit(struct drm_atomic_st + * should always call this function from their + * &drm_mode_config_funcs.atomic_commit hook. + * ++ * Drivers that need to extend the commit setup to private objects can use the ++ * &drm_mode_config_helper_funcs.atomic_commit_setup hook. ++ * + * To be able to use this support drivers need to use a few more helper + * functions. drm_atomic_helper_wait_for_dependencies() must be called before + * actually committing the hardware state, and for nonblocking commits this call +@@ -2082,8 +2085,11 @@ int drm_atomic_helper_setup_commit(struc + struct drm_plane *plane; + struct drm_plane_state *old_plane_state, *new_plane_state; + struct drm_crtc_commit *commit; ++ const struct drm_mode_config_helper_funcs *funcs; + int i, ret; + ++ funcs = state->dev->mode_config.helper_private; ++ + for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) { + commit = kzalloc(sizeof(*commit), GFP_KERNEL); + if (!commit) +@@ -2160,6 +2166,9 @@ int drm_atomic_helper_setup_commit(struc + new_plane_state->commit = drm_crtc_commit_get(commit); + } + ++ if (funcs && funcs->atomic_commit_setup) ++ return funcs->atomic_commit_setup(state); ++ + return 0; + } + EXPORT_SYMBOL(drm_atomic_helper_setup_commit); +--- a/include/drm/drm_modeset_helper_vtables.h ++++ b/include/drm/drm_modeset_helper_vtables.h +@@ -1396,6 +1396,27 @@ struct drm_mode_config_helper_funcs { + * drm_atomic_helper_commit_tail(). + */ + void (*atomic_commit_tail)(struct drm_atomic_state *state); ++ ++ /** ++ * @atomic_commit_setup: ++ * ++ * This hook is used by the default atomic_commit() hook implemented in ++ * drm_atomic_helper_commit() together with the nonblocking helpers (see ++ * drm_atomic_helper_setup_commit()) to extend the DRM commit setup. It ++ * is not used by the atomic helpers. ++ * ++ * This function is called at the end of ++ * drm_atomic_helper_setup_commit(), so once the commit has been ++ * properly setup across the generic DRM object states. It allows ++ * drivers to do some additional commit tracking that isn't related to a ++ * CRTC, plane or connector, tracked in a &drm_private_obj structure. ++ * ++ * Note that the documentation of &drm_private_obj has more details on ++ * how one should implement this. ++ * ++ * This hook is optional. ++ */ ++ int (*atomic_commit_setup)(struct drm_atomic_state *state); + }; + + #endif |