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drm/atomic-helper: roll out commit synchronization

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To facilitate easier reviewing this is split out from the overall
nonblocking commit rework. It just rolls out the helper functions
and uses them in the main drm_atomic_helper_commit() function
to make it clear where in the flow they're used.

The next patch will actually split drm_atomic_helper_commit() into
2 pieces, with the tail being run asynchronously from a worker.

v2: Improve kerneldocs (Maarten).

v3: Don't convert ERESTARTSYS to EINTR (Maarten). Also don't fail if
the wait succeed in stall_check - we need to convert that case (it
returns the remaining jiffies) to 0 for success.

v4: Switch to long for wait_for_completion_timeout return value
everywhere (Maarten).

v5: Fix miscaped function in kerneldoc (Maarten).

Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Tested-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Tomeu Vizoso <tomeu.vizoso@gmail.com>
Cc: Daniel Stone <daniels@collabora.com>
Tested-by: Liviu Dudau <Liviu.Dudau@arm.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1465398936-22305-1-git-send-email-daniel.vetter@ffwll.ch
This commit is contained in:
Daniel Vetter 2016-06-08 17:15:36 +02:00
parent 3b24f7d675
commit a095caa7f5
2 changed files with 354 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

347
drivers/gpu/drm/drm_atomic_helper.c
View file

@ -1157,6 +1157,10 @@ int drm_atomic_helper_commit(struct drm_device *dev,
if (nonblock)
return -EBUSY;
ret = drm_atomic_helper_setup_commit(state, nonblock);
if (ret)
return ret;
ret = drm_atomic_helper_prepare_planes(dev, state);
if (ret)
return ret;
@ -1187,16 +1191,22 @@ int drm_atomic_helper_commit(struct drm_device *dev,
drm_atomic_helper_wait_for_fences(dev, state);
drm_atomic_helper_wait_for_dependencies(state);
drm_atomic_helper_commit_modeset_disables(dev, state);
drm_atomic_helper_commit_planes(dev, state, false);
drm_atomic_helper_commit_modeset_enables(dev, state);
drm_atomic_helper_commit_hw_done(state);
drm_atomic_helper_wait_for_vblanks(dev, state);
drm_atomic_helper_cleanup_planes(dev, state);
drm_atomic_helper_commit_cleanup_done(state);
drm_atomic_state_free(state);
return 0;
@ -1241,6 +1251,306 @@ EXPORT_SYMBOL(drm_atomic_helper_commit);
* being displayed.
*/
static int stall_checks(struct drm_crtc *crtc, bool nonblock)
{
struct drm_crtc_commit *commit, *stall_commit = NULL;
bool completed = true;
int i;
long ret = 0;
spin_lock(&crtc->commit_lock);
i = 0;
list_for_each_entry(commit, &crtc->commit_list, commit_entry) {
if (i == 0) {
completed = try_wait_for_completion(&commit->flip_done);
/* Userspace is not allowed to get ahead of the previous
* commit with nonblocking ones. */
if (!completed && nonblock) {
spin_unlock(&crtc->commit_lock);
return -EBUSY;
}
} else if (i == 1) {
stall_commit = commit;
drm_crtc_commit_get(stall_commit);
} else
break;
i++;
}
spin_unlock(&crtc->commit_lock);
if (!stall_commit)
return 0;
/* We don't want to let commits get ahead of cleanup work too much,
* stalling on 2nd previous commit means triple-buffer won't ever stall.
*/
ret = wait_for_completion_interruptible_timeout(&commit->cleanup_done,
10*HZ);
if (ret == 0)
DRM_ERROR("[CRTC:%d:%s] cleanup_done timed out\n",
crtc->base.id, crtc->name);
drm_crtc_commit_put(stall_commit);
return ret < 0 ? ret : 0;
}
/**
* drm_atomic_helper_setup_commit - setup possibly nonblocking commit
* @state: new modeset state to be committed
* @nonblock: whether nonblocking behavior is requested.
*
* This function prepares @state to be used by the atomic helper's support for
* nonblocking commits. Drivers using the nonblocking commit infrastructure
* should always call this function from their ->atomic_commit 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
* must be placed in the async worker. See also drm_atomic_helper_swap_state()
* and it's stall parameter, for when a driver's commit hooks look at the
* ->state pointers of struct &drm_crtc, &drm_plane or &drm_connector directly.
*
* Completion of the hardware commit step must be signalled using
* drm_atomic_helper_commit_hw_done(). After this step the driver is not allowed
* to read or change any permanent software or hardware modeset state. The only
* exception is state protected by other means than &drm_modeset_lock locks.
* Only the free standing @state with pointers to the old state structures can
* be inspected, e.g. to clean up old buffers using
* drm_atomic_helper_cleanup_planes().
*
* At the very end, before cleaning up @state drivers must call
* drm_atomic_helper_commit_cleanup_done().
*
* This is all implemented by in drm_atomic_helper_commit(), giving drivers a
* complete and esay-to-use default implementation of the atomic_commit() hook.
*
* The tracking of asynchronously executed and still pending commits is done
* using the core structure &drm_crtc_commit.
*
* By default there's no need to clean up resources allocated by this function
* explicitly: drm_atomic_state_default_clear() will take care of that
* automatically.
*
* Returns:
*
* 0 on success. -EBUSY when userspace schedules nonblocking commits too fast,
* -ENOMEM on allocation failures and -EINTR when a signal is pending.
*/
int drm_atomic_helper_setup_commit(struct drm_atomic_state *state,
bool nonblock)
{
struct drm_crtc *crtc;
struct drm_crtc_state *crtc_state;
struct drm_crtc_commit *commit;
int i, ret;
for_each_crtc_in_state(state, crtc, crtc_state, i) {
commit = kzalloc(sizeof(*commit), GFP_KERNEL);
if (!commit)
return -ENOMEM;
init_completion(&commit->flip_done);
init_completion(&commit->hw_done);
init_completion(&commit->cleanup_done);
INIT_LIST_HEAD(&commit->commit_entry);
kref_init(&commit->ref);
commit->crtc = crtc;
state->crtcs[i].commit = commit;
ret = stall_checks(crtc, nonblock);
if (ret)
return ret;
/* Drivers only send out events when at least either current or
* new CRTC state is active. Complete right away if everything
* stays off. */
if (!crtc->state->active && !crtc_state->active) {
complete_all(&commit->flip_done);
continue;
}
/* Legacy cursor updates are fully unsynced. */
if (state->legacy_cursor_update) {
complete_all(&commit->flip_done);
continue;
}
if (!crtc_state->event) {
commit->event = kzalloc(sizeof(*commit->event),
GFP_KERNEL);
if (!commit->event)
return -ENOMEM;
crtc_state->event = commit->event;
}
crtc_state->event->base.completion = &commit->flip_done;
}
return 0;
}
EXPORT_SYMBOL(drm_atomic_helper_setup_commit);
static struct drm_crtc_commit *preceeding_commit(struct drm_crtc *crtc)
{
struct drm_crtc_commit *commit;
int i = 0;
list_for_each_entry(commit, &crtc->commit_list, commit_entry) {
/* skip the first entry, that's the current commit */
if (i == 1)
return commit;
i++;
}
return NULL;
}
/**
* drm_atomic_helper_wait_for_dependencies - wait for required preceeding commits
* @state: new modeset state to be committed
*
* This function waits for all preceeding commits that touch the same CRTC as
* @state to both be committed to the hardware (as signalled by
* drm_atomic_helper_commit_hw_done) and executed by the hardware (as signalled
* by calling drm_crtc_vblank_send_event on the event member of
* &drm_crtc_state).
*
* This is part of the atomic helper support for nonblocking commits, see
* drm_atomic_helper_setup_commit() for an overview.
*/
void drm_atomic_helper_wait_for_dependencies(struct drm_atomic_state *state)
{
struct drm_crtc *crtc;
struct drm_crtc_state *crtc_state;
struct drm_crtc_commit *commit;
int i;
long ret;
for_each_crtc_in_state(state, crtc, crtc_state, i) {
spin_lock(&crtc->commit_lock);
commit = preceeding_commit(crtc);
if (commit)
drm_crtc_commit_get(commit);
spin_unlock(&crtc->commit_lock);
if (!commit)
continue;
ret = wait_for_completion_timeout(&commit->hw_done,
10*HZ);
if (ret == 0)
DRM_ERROR("[CRTC:%d:%s] hw_done timed out\n",
crtc->base.id, crtc->name);
/* Currently no support for overwriting flips, hence
* stall for previous one to execute completely. */
ret = wait_for_completion_timeout(&commit->flip_done,
10*HZ);
if (ret == 0)
DRM_ERROR("[CRTC:%d:%s] flip_done timed out\n",
crtc->base.id, crtc->name);
drm_crtc_commit_put(commit);
}
}
EXPORT_SYMBOL(drm_atomic_helper_wait_for_dependencies);
/**
* drm_atomic_helper_commit_hw_done - setup possible nonblocking commit
* @state: new modeset state to be committed
*
* This function is used to signal completion of the hardware commit step. After
* this step the driver is not allowed to read or change any permanent software
* or hardware modeset state. The only exception is state protected by other
* means than &drm_modeset_lock locks.
*
* Drivers should try to postpone any expensive or delayed cleanup work after
* this function is called.
*
* This is part of the atomic helper support for nonblocking commits, see
* drm_atomic_helper_setup_commit() for an overview.
*/
void drm_atomic_helper_commit_hw_done(struct drm_atomic_state *state)
{
struct drm_crtc *crtc;
struct drm_crtc_state *crtc_state;
struct drm_crtc_commit *commit;
int i;
for_each_crtc_in_state(state, crtc, crtc_state, i) {
commit = state->crtcs[i].commit;
if (!commit)
continue;
/* backend must have consumed any event by now */
WARN_ON(crtc->state->event);
spin_lock(&crtc->commit_lock);
complete_all(&commit->hw_done);
spin_unlock(&crtc->commit_lock);
}
}
EXPORT_SYMBOL(drm_atomic_helper_commit_hw_done);
/**
* drm_atomic_helper_commit_cleanup_done - signal completion of commit
* @state: new modeset state to be committed
*
* This signals completion of the atomic update @state, including any cleanup
* work. If used, it must be called right before calling
* drm_atomic_state_free().
*
* This is part of the atomic helper support for nonblocking commits, see
* drm_atomic_helper_setup_commit() for an overview.
*/
void drm_atomic_helper_commit_cleanup_done(struct drm_atomic_state *state)
{
struct drm_crtc *crtc;
struct drm_crtc_state *crtc_state;
struct drm_crtc_commit *commit;
int i;
long ret;
for_each_crtc_in_state(state, crtc, crtc_state, i) {
commit = state->crtcs[i].commit;
if (WARN_ON(!commit))
continue;
spin_lock(&crtc->commit_lock);
complete_all(&commit->cleanup_done);
WARN_ON(!try_wait_for_completion(&commit->hw_done));
/* commit_list borrows our reference, need to remove before we
* clean up our drm_atomic_state. But only after it actually
* completed, otherwise subsequent commits won't stall properly. */
if (try_wait_for_completion(&commit->flip_done)) {
list_del(&commit->commit_entry);
spin_unlock(&crtc->commit_lock);
continue;
}
spin_unlock(&crtc->commit_lock);
/* We must wait for the vblank event to signal our completion
* before releasing our reference, since the vblank work does
* not hold a reference of its own. */
ret = wait_for_completion_timeout(&commit->flip_done,
10*HZ);
if (ret == 0)
DRM_ERROR("[CRTC:%d:%s] flip_done timed out\n",
crtc->base.id, crtc->name);
spin_lock(&crtc->commit_lock);
list_del(&commit->commit_entry);
spin_unlock(&crtc->commit_lock);
}
}
EXPORT_SYMBOL(drm_atomic_helper_commit_cleanup_done);
/**
* drm_atomic_helper_prepare_planes - prepare plane resources before commit
* @dev: DRM device
@ -1560,17 +1870,45 @@ EXPORT_SYMBOL(drm_atomic_helper_cleanup_planes);
*
* 5. Call drm_atomic_helper_cleanup_planes() with @state, which since step 3
* contains the old state. Also do any other cleanup required with that state.
*
* @stall must be set when nonblocking commits for this driver directly access
* the ->state pointer of &drm_plane, &drm_crtc or &drm_connector. With the
* current atomic helpers this is almost always the case, since the helpers
* don't pass the right state structures to the callbacks.
*/
void drm_atomic_helper_swap_state(struct drm_atomic_state *state,
bool stall)
{
int i;
long ret;
struct drm_connector *connector;
struct drm_connector_state *conn_state;
struct drm_crtc *crtc;
struct drm_crtc_state *crtc_state;
struct drm_plane *plane;
struct drm_plane_state *plane_state;
struct drm_crtc_commit *commit;
if (stall) {
for_each_crtc_in_state(state, crtc, crtc_state, i) {
spin_lock(&crtc->commit_lock);
commit = list_first_entry_or_null(&crtc->commit_list,
struct drm_crtc_commit, commit_entry);
if (commit)
drm_crtc_commit_get(commit);
spin_unlock(&crtc->commit_lock);
if (!commit)
continue;
ret = wait_for_completion_timeout(&commit->hw_done,
10*HZ);
if (ret == 0)
DRM_ERROR("[CRTC:%d:%s] hw_done timed out\n",
crtc->base.id, crtc->name);
drm_crtc_commit_put(commit);
}
}
for_each_connector_in_state(state, connector, conn_state, i) {
connector->state->state = state;
@ -1582,6 +1920,15 @@ void drm_atomic_helper_swap_state(struct drm_atomic_state *state,
crtc->state->state = state;
swap(state->crtcs[i].state, crtc->state);
crtc->state->state = NULL;
if (state->crtcs[i].commit) {
spin_lock(&crtc->commit_lock);
list_add(&state->crtcs[i].commit->commit_entry,
&crtc->commit_list);
spin_unlock(&crtc->commit_lock);
state->crtcs[i].commit->event = NULL;
}
}
for_each_plane_in_state(state, plane, plane_state, i) {

7
include/drm/drm_atomic_helper.h
View file

@ -74,6 +74,13 @@ void drm_atomic_helper_disable_planes_on_crtc(struct drm_crtc *crtc,
void drm_atomic_helper_swap_state(struct drm_atomic_state *state,
bool stall);
/* nonblocking commit helpers */
int drm_atomic_helper_setup_commit(struct drm_atomic_state *state,
bool nonblock);
void drm_atomic_helper_wait_for_dependencies(struct drm_atomic_state *state);
void drm_atomic_helper_commit_hw_done(struct drm_atomic_state *state);
void drm_atomic_helper_commit_cleanup_done(struct drm_atomic_state *state);
/* implementations for legacy interfaces */
int drm_atomic_helper_update_plane(struct drm_plane *plane,
struct drm_crtc *crtc,