diff options
| author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2016-05-30 11:10:49 +0200 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2016-05-30 11:18:26 +0200 |
| commit | 0645de5a4c22638170f6e0bb31a0b1c9f52daf93 (patch) | |
| tree | a53d62183c9eb23dd055e29d656789b86e7bd700 | |
| parent | f55f1701168de914f3d872398d649d330c348f27 (diff) | |
drm/doc: Unify KMS Locking docs
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Acked-by: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1464599449-12509-1-git-send-email-daniel.vetter@ffwll.ch
| -rw-r--r-- | Documentation/DocBook/gpu.tmpl | 16 | ||||
| -rw-r--r-- | drivers/gpu/drm/drm_modeset_lock.c | 11 |
2 files changed, 9 insertions, 18 deletions
diff --git a/Documentation/DocBook/gpu.tmpl b/Documentation/DocBook/gpu.tmpl index 90dbdb5087c4..221a4929ca59 100644 --- a/Documentation/DocBook/gpu.tmpl +++ b/Documentation/DocBook/gpu.tmpl @@ -1092,22 +1092,6 @@ int max_width, max_height;</synopsis> operation. </para> </sect2> - <sect2> - <title>Locking</title> - <para> - Beside some lookup structures with their own locking (which is hidden - behind the interface functions) most of the modeset state is protected - by the <code>dev-<mode_config.lock</code> mutex and additionally - per-crtc locks to allow cursor updates, pageflips and similar operations - to occur concurrently with background tasks like output detection. - Operations which cross domains like a full modeset always grab all - locks. Drivers there need to protect resources shared between crtcs with - additional locking. They also need to be careful to always grab the - relevant crtc locks if a modset functions touches crtc state, e.g. for - load detection (which does only grab the <code>mode_config.lock</code> - to allow concurrent screen updates on live crtcs). - </para> - </sect2> </sect1> <!-- Internals: kms initialization and cleanup --> diff --git a/drivers/gpu/drm/drm_modeset_lock.c b/drivers/gpu/drm/drm_modeset_lock.c index e3a4adf03e7b..f33ebe638a28 100644 --- a/drivers/gpu/drm/drm_modeset_lock.c +++ b/drivers/gpu/drm/drm_modeset_lock.c @@ -30,12 +30,12 @@ * * As KMS moves toward more fine grained locking, and atomic ioctl where * userspace can indirectly control locking order, it becomes necessary - * to use ww_mutex and acquire-contexts to avoid deadlocks. But because + * to use &ww_mutex and acquire-contexts to avoid deadlocks. But because * the locking is more distributed around the driver code, we want a bit * of extra utility/tracking out of our acquire-ctx. This is provided * by drm_modeset_lock / drm_modeset_acquire_ctx. * - * For basic principles of ww_mutex, see: Documentation/locking/ww-mutex-design.txt + * For basic principles of &ww_mutex, see: Documentation/locking/ww-mutex-design.txt * * The basic usage pattern is to: * @@ -51,6 +51,13 @@ * ... do stuff ... * 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 + * dev->mode_config.lock, for protecting everything else. Mostly this means + * probe state of connectors, and preventing hotplug add/removal of connectors. + * + * Finally there's a bunch of dedicated locks to protect drm core internal + * lists and lookup data structures. */ /** |