Add {begin,end}_fb_access helpers to run at the beginning and end of
an atomic commit. The begin_fb_access helper aquires resources that
are necessary to perform the atomic commit. It it similar to prepare_fb,
except that the resources are to be released at the end of the commit.
Resources acquired by prepare_fb are held until after the next pageflip.
The end_fb_access helper performs the corresponding resource cleanup.
Atomic helpers call it with the new plane state. This is differnt from
cleanup_fb, which releases resources of the old plane state.
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
---
drivers/gpu/drm/drm_atomic_helper.c | 34 ++++++++++++++++++--
drivers/gpu/drm/drm_gem_atomic_helper.c | 19 ++++++-----
drivers/gpu/drm/drm_simple_kms_helper.c | 26 +++++++++++++++
include/drm/drm_modeset_helper_vtables.h | 41 +++++++++++++++++++++++-
include/drm/drm_simple_kms_helper.h | 20 ++++++++++++
5 files changed, 126 insertions(+), 14 deletions(-)
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 1a586b3c454b4..d579fd8f7cb83 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -2536,7 +2536,7 @@ int drm_atomic_helper_prepare_planes(struct drm_device *dev,
if (funcs->prepare_fb) {
ret = funcs->prepare_fb(plane, new_plane_state);
if (ret)
- goto fail;
+ goto fail_prepare_fb;
} else {
WARN_ON_ONCE(funcs->cleanup_fb);
@@ -2545,13 +2545,34 @@ int drm_atomic_helper_prepare_planes(struct drm_device *dev,
ret = drm_gem_plane_helper_prepare_fb(plane, new_plane_state);
if (ret)
- goto fail;
+ goto fail_prepare_fb;
+ }
+ }
+
+ for_each_new_plane_in_state(state, plane, new_plane_state, i) {
+ const struct drm_plane_helper_funcs *funcs = plane->helper_private;
+
+ if (funcs->begin_fb_access) {
+ ret = funcs->begin_fb_access(plane, new_plane_state);
+ if (ret)
+ goto fail_begin_fb_access;
}
}
return 0;
-fail:
+fail_begin_fb_access:
+ for_each_new_plane_in_state(state, plane, new_plane_state, j) {
+ const struct drm_plane_helper_funcs *funcs = plane->helper_private;
+
+ if (j >= i)
+ continue;
+
+ if (funcs->end_fb_access)
+ funcs->end_fb_access(plane, new_plane_state);
+ }
+ i = j; /* set i to upper limit to cleanup all planes */
+fail_prepare_fb:
for_each_new_plane_in_state(state, plane, new_plane_state, j) {
const struct drm_plane_helper_funcs *funcs;
@@ -2827,6 +2848,13 @@ void drm_atomic_helper_cleanup_planes(struct drm_device *dev,
struct drm_plane_state *old_plane_state, *new_plane_state;
int i;
+ for_each_oldnew_plane_in_state(old_state, plane, old_plane_state, new_plane_state, i) {
+ const struct drm_plane_helper_funcs *funcs = plane->helper_private;
+
+ if (funcs->end_fb_access)
+ funcs->end_fb_access(plane, new_plane_state);
+ }
+
for_each_oldnew_plane_in_state(old_state, plane, old_plane_state, new_plane_state, i) {
const struct drm_plane_helper_funcs *funcs;
struct drm_plane_state *plane_state;
diff --git a/drivers/gpu/drm/drm_gem_atomic_helper.c b/drivers/gpu/drm/drm_gem_atomic_helper.c
index b6a0110eb64af..1de0a08afd86e 100644
--- a/drivers/gpu/drm/drm_gem_atomic_helper.c
+++ b/drivers/gpu/drm/drm_gem_atomic_helper.c
@@ -414,16 +414,14 @@ void drm_gem_cleanup_shadow_fb(struct drm_plane *plane, struct drm_plane_state *
EXPORT_SYMBOL(drm_gem_cleanup_shadow_fb);
/**
- * drm_gem_simple_kms_prepare_shadow_fb - prepares shadow framebuffers
+ * drm_gem_simple_kms_begin_shadow_fb_access - prepares shadow framebuffers for CPU access
* @pipe: the simple display pipe
* @plane_state: the plane state of type struct drm_shadow_plane_state
*
- * This function implements struct drm_simple_display_funcs.prepare_fb. It
- * maps all buffer objects of the plane's framebuffer into kernel address
- * space and stores them in struct drm_shadow_plane_state.map. The
- * framebuffer will be synchronized as part of the atomic commit.
+ * This function implements struct drm_simple_display_funcs.begin_fb_access.
*
- * See drm_gem_simple_kms_cleanup_shadow_fb() for cleanup.
+ * See drm_gem_begin_shadow_fb_access() for details and
+ * drm_gem_simple_kms_cleanup_shadow_fb() for cleanup.
*
* Returns:
* 0 on success, or a negative errno code otherwise.
@@ -436,14 +434,15 @@ int drm_gem_simple_kms_prepare_shadow_fb(struct drm_simple_display_pipe *pipe,
EXPORT_SYMBOL(drm_gem_simple_kms_prepare_shadow_fb);
/**
- * drm_gem_simple_kms_cleanup_shadow_fb - releases shadow framebuffers
+ * drm_gem_simple_kms_end_shadow_fb_access - releases shadow framebuffers from CPU access
* @pipe: the simple display pipe
* @plane_state: the plane state of type struct drm_shadow_plane_state
*
- * This function implements struct drm_simple_display_funcs.cleanup_fb.
- * This function unmaps all buffer objects of the plane's framebuffer.
+ * This function implements struct drm_simple_display_funcs.end_fb_access.
+ * It undoes all effects of drm_gem_simple_kms_begin_shadow_fb_access() in
+ * reverse order.
*
- * See drm_gem_simple_kms_prepare_shadow_fb().
+ * See drm_gem_simple_kms_begin_shadow_fb_access().
*/
void drm_gem_simple_kms_cleanup_shadow_fb(struct drm_simple_display_pipe *pipe,
struct drm_plane_state *plane_state)
diff --git a/drivers/gpu/drm/drm_simple_kms_helper.c b/drivers/gpu/drm/drm_simple_kms_helper.c
index 31233c6ae3c42..3ef420ec4534a 100644
--- a/drivers/gpu/drm/drm_simple_kms_helper.c
+++ b/drivers/gpu/drm/drm_simple_kms_helper.c
@@ -285,6 +285,30 @@ static void drm_simple_kms_plane_cleanup_fb(struct drm_plane *plane,
pipe->funcs->cleanup_fb(pipe, state);
}
+static int drm_simple_kms_plane_begin_fb_access(struct drm_plane *plane,
+ struct drm_plane_state *new_plane_state)
+{
+ struct drm_simple_display_pipe *pipe;
+
+ pipe = container_of(plane, struct drm_simple_display_pipe, plane);
+ if (!pipe->funcs || !pipe->funcs->begin_fb_access)
+ return 0;
+
+ return pipe->funcs->begin_fb_access(pipe, new_plane_state);
+}
+
+static void drm_simple_kms_plane_end_fb_access(struct drm_plane *plane,
+ struct drm_plane_state *new_plane_state)
+{
+ struct drm_simple_display_pipe *pipe;
+
+ pipe = container_of(plane, struct drm_simple_display_pipe, plane);
+ if (!pipe->funcs || !pipe->funcs->end_fb_access)
+ return;
+
+ pipe->funcs->end_fb_access(pipe, new_plane_state);
+}
+
static bool drm_simple_kms_format_mod_supported(struct drm_plane *plane,
uint32_t format,
uint64_t modifier)
@@ -295,6 +319,8 @@ static bool drm_simple_kms_format_mod_supported(struct drm_plane *plane,
static const struct drm_plane_helper_funcs drm_simple_kms_plane_helper_funcs = {
.prepare_fb = drm_simple_kms_plane_prepare_fb,
.cleanup_fb = drm_simple_kms_plane_cleanup_fb,
+ .begin_fb_access = drm_simple_kms_plane_begin_fb_access,
+ .end_fb_access = drm_simple_kms_plane_end_fb_access,
.atomic_check = drm_simple_kms_plane_atomic_check,
.atomic_update = drm_simple_kms_plane_atomic_update,
};
diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h
index fafa70ac1337f..d9f2254a039aa 100644
--- a/include/drm/drm_modeset_helper_vtables.h
+++ b/include/drm/drm_modeset_helper_vtables.h
@@ -1184,11 +1184,20 @@ struct drm_plane_helper_funcs {
* can call drm_gem_plane_helper_prepare_fb() from their @prepare_fb
* hook.
*
+ * The resources acquired in @prepare_fb persist after the end of
+ * the atomic commit. Resources that can be release at the commit's end
+ * should be acquired in @begin_fb_access and released in @end_fb_access.
+ * For example, a GEM buffer's pin operation belongs into @prepare_fb to
+ * keep the buffer pinned after the commit. But a vmap operation for
+ * shadow-plane helpers belongs into @begin_fb_access, so that atomic
+ * helpers remove the mapping at the end of the commit.
+ *
* The helpers will call @cleanup_fb with matching arguments for every
* successful call to this hook.
*
* This callback is used by the atomic modeset helpers and by the
- * transitional plane helpers, but it is optional.
+ * transitional plane helpers, but it is optional. See @begin_fb_access
+ * for preparing per-commit resources.
*
* RETURNS:
*
@@ -1211,6 +1220,36 @@ struct drm_plane_helper_funcs {
void (*cleanup_fb)(struct drm_plane *plane,
struct drm_plane_state *old_state);
+ /**
+ * @begin_fb_access:
+ *
+ * This hook prepares the plane for access during an atomic commit.
+ * In contrast to @prepare_fb, resources acquired in @begin_fb_access,
+ * are released at the end of the atomic commit in @end_fb_access.
+ *
+ * For example, with shadow-plane helpers, the GEM buffer's vmap
+ * operation belongs into @begin_fb_access, so that the buffer's
+ * memory will be unmapped at the end of the commit in @end_fb_access.
+ * But a GEM buffer's pin operation belongs into @prepare_fb
+ * to keep the buffer pinned after the commit.
+ *
+ * The callback is used by the atomic modeset helpers, but it is optional.
+ * See @end_fb_cleanup for undoing the effects of @begin_fb_access and
+ * @prepare_fb for acquiring resources until the next pageflip.
+ *
+ * Returns:
+ * 0 on success, or a negative errno code otherwise.
+ */
+ int (*begin_fb_access)(struct drm_plane *plane, struct drm_plane_state *new_plane_state);
+
+ /**
+ * @end_fb_access:
+ *
+ * This hook cleans up resources allocated by @begin_fb_access. It it called
+ * at the end of a commit for the new plane state.
+ */
+ void (*end_fb_access)(struct drm_plane *plane, struct drm_plane_state *new_plane_state);
+
/**
* @atomic_check:
*
diff --git a/include/drm/drm_simple_kms_helper.h b/include/drm/drm_simple_kms_helper.h
index 0b3647e614dd3..2298fe3af4cd7 100644
--- a/include/drm/drm_simple_kms_helper.h
+++ b/include/drm/drm_simple_kms_helper.h
@@ -135,6 +135,26 @@ struct drm_simple_display_pipe_funcs {
void (*cleanup_fb)(struct drm_simple_display_pipe *pipe,
struct drm_plane_state *plane_state);
+ /**
+ * @begin_fb_access:
+ *
+ * Optional, called by &drm_plane_helper_funcs.begin_fb_access. Please read
+ * the documentation for the &drm_plane_helper_funcs.begin_fb_access hook for
+ * more details.
+ */
+ int (*begin_fb_access)(struct drm_simple_display_pipe *pipe,
+ struct drm_plane_state *new_plane_state);
+
+ /**
+ * @end_fb_access:
+ *
+ * Optional, called by &drm_plane_helper_funcs.end_fb_access. Please read
+ * the documentation for the &drm_plane_helper_funcs.end_fb_access hook for
+ * more details.
+ */
+ void (*end_fb_access)(struct drm_simple_display_pipe *pipe,
+ struct drm_plane_state *plane_state);
+
/**
* @enable_vblank:
*
--
2.38.0
