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| author | Liviu Dudau <Liviu.Dudau@arm.com> | 2017-07-20 19:07:48 +0300 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2017-07-26 14:45:08 +0300 |
| commit | fc2157b6edcd68e99a51323bae4c21c273699ca7 (patch) | |
| tree | a71692e1e6d27e2b96348a37250f5bd39b4862ca /drivers/gpu/drm | |
| parent | 14693a08160ee38b05975260029811d560d7a34c (diff) | |
| download | linux-fc2157b6edcd68e99a51323bae4c21c273699ca7.tar.xz | |
drm: Improve kerneldoc for drm_modeset_lock
Explain better when the drm_modeset_acquire_ctx parameter can
be skipped for drm_modeset_lock() call.
Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20170720160748.12856-1-Liviu.Dudau@arm.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'drivers/gpu/drm')
| -rw-r--r-- | drivers/gpu/drm/drm_modeset_lock.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/drivers/gpu/drm/drm_modeset_lock.c b/drivers/gpu/drm/drm_modeset_lock.c index 64ef09a6cccb..af4e906c630d 100644 --- a/drivers/gpu/drm/drm_modeset_lock.c +++ b/drivers/gpu/drm/drm_modeset_lock.c @@ -52,7 +52,12 @@ * drm_modeset_drop_locks(&ctx); * drm_modeset_acquire_fini(&ctx); * - * On top of of these per-object locks using &ww_mutex there's also an overall + * If all that is needed is a single modeset lock, then the &struct + * drm_modeset_acquire_ctx is not needed and the locking can be simplified + * by passing a NULL instead of ctx in the drm_modeset_lock() + * call and, when done, by calling drm_modeset_unlock(). + * + * On top of these per-object locks using &ww_mutex there's also an overall * &drm_mode_config.mutex, for protecting everything else. Mostly this means * probe state of connectors, and preventing hotplug add/removal of connectors. * @@ -313,11 +318,14 @@ EXPORT_SYMBOL(drm_modeset_lock_init); * @lock: lock to take * @ctx: acquire ctx * - * If ctx is not NULL, then its ww acquire context is used and the + * If @ctx is not NULL, then its ww acquire context is used and the * lock will be tracked by the context and can be released by calling * drm_modeset_drop_locks(). If -EDEADLK is returned, this means a * deadlock scenario has been detected and it is an error to attempt * to take any more locks without first calling drm_modeset_backoff(). + * + * If @ctx is NULL then the function call behaves like a normal, + * non-nesting mutex_lock() call. */ int drm_modeset_lock(struct drm_modeset_lock *lock, struct drm_modeset_acquire_ctx *ctx) |