Currently the functions that initialize and tear down a connector
iterator use the _get() and _put() suffixes. However, these suffixes
are typically used by reference counting functions.
Make these function names a little more consistent by changing the
suffixes to _begin() and _end(), which is a fairly common pattern in
the rest of the Linux kernel.
Suggested-by: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170228144643.5668-8-thierry.reding@gmail.com
Subsequent patches will introduce reference counting APIs that are more
consistent with similar APIs throughout the Linux kernel. These APIs use
the _get() and _put() suffixes and will collide with this existing
function.
Rename the function to drm_mode_object_add() which is a slightly more
accurate description of what it does. Also the kerneldoc for this
function gives an indication that it's badly named because it doesn't
actually acquire a reference to anything.
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170228144643.5668-2-thierry.reding@gmail.com
I just learned that &struct_name.member_name works and looks pretty
even. It doesn't (yet) link to the member directly though, which would
be really good for big structures or vfunc tables (where the
per-member kerneldoc tends to be long).
Also some minor drive-by polish where it makes sense, I read a lot
of docs ...
v2: Review from Eric.
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170125062657.19270-4-daniel.vetter@ffwll.ch
sed -e 's/\( \* .*\)struct &\([_a-z]*\)/\1\&struct \2/' -i
Originally I wasnt a friend of this style because I thought a
line-break between the "&struct" and "foo" part would break it. But a
quick test shows that " * &struct \n * foo\n" works pefectly well with
current kernel-doc. So time to mass-apply these changes!
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1483044517-5770-6-git-send-email-daniel.vetter@ffwll.ch
The requirements for connector_list locking are a bit tricky:
- We need to be able to jump over zombie conectors (i.e. with refcount
== 0, but not yet removed from the list). If instead we require that
there's no zombies on the list then the final kref_put must happen
under the list protection lock, which means that locking context
leaks all over the place. Not pretty - better to deal with zombies
and wrap the locking just around the list_del in the destructor.
- When we walk the list we must _not_ hold the connector list lock. We
walk the connector list at an absolutely massive amounts of places,
if all those places can't ever call drm_connector_unreference the
code would get unecessarily complicated.
- connector_list needs it own lock, again too many places that walk it
that we could reuse e.g. mode_config.mutex without resulting in
inversions.
- Lots of code uses these loops to look-up a connector, i.e. they want
to be able to call drm_connector_reference. But on the other hand we
want connectors to stay on that list until they're dead (i.e.
connector_list can't hold a full reference), which means despite the
"can't hold lock for the loop body" rule we need to make sure a
connector doesn't suddenly become a zombie.
At first Dave&I discussed various horror-show approaches using srcu,
but turns out it's fairly easy:
- For the loop body we always hold an additional reference to the
current connector. That means it can't zombify, and it also means
it'll stay on the list, which means we can use it as our iterator to
find the next connector.
- When we try to find the next connector we only have to jump over
zombies. To make sure we don't chase bad pointers that entire loop
is protected with the new connect_list_lock spinlock. And because we
know that we're starting out with a non-zombie (need to drop our
reference for the old connector only after we have our new one),
we're guranteed to still be on the connector_list and either find
the next non-zombie or complete the iteration.
- Only downside is that we need to make sure that the temporary
reference for the loop body doesn't leak. iter_get/put() functions +
lockdep make sure that's the case.
- To avoid a flag day the new iterator macro has an _iter postfix. We
can rename it back once all the users of the unsafe version are gone
(there's about 100 list walkers for the connector_list).
For now this patch only converts all the list walking in the core,
leaving helpers and drivers for later patches. The nice thing is that
we can now finally remove 2 FIXME comments from the
register/unregister functions.
v2:
- use irqsafe spinlocks, so that we can use this in drm_state_dump
too.
- nuke drm_modeset_lock_all from drm_connector_init, now entirely
cargo-culted nonsense.
v3:
- do {} while (!kref_get_unless_zero), makes for a tidier loop (Dave).
- pretty kerneldoc
- add EXPORT_SYMBOL, helpers&drivers are supposed to use this.
v4: Change lockdep annotations to only check whether we release the
iter fake lock again (i.e. make sure that iter_put is called), but
not check any locking dependecies itself. That seams to require a
recursive read lock in trylock mode.
Cc: Dave Airlie <airlied@gmail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161213230814.19598-6-daniel.vetter@ffwll.ch
Encoders&planes can't be hotplugged, we dont need locking for this
since it's all single-threaded driver setup/teardown code. CRTCs
already don't grab locks.
While at it I noticed that plane's are missing the
drm_modeset_lock_fini() call, so add it.
Reviewed-by: Frank Binns <frank.binns@imgtec.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161129094538.9650-1-daniel.vetter@ffwll.ch
Corrected typo in bridge and encoder comparison. Also, added a one-line
encoder description from the previous documentation.
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1474324848-6446-1-git-send-email-dhinakaran.pandiyan@intel.com
- Move missing bits into struct drm_encoder docs.
- Explain that encoders are 95% internal and only 5% uapi, and that in
general the uapi part is broken.
- Remove verbose comments for functions not exposed to drivers.
v2: Review from Archit:
- Appease checkpatch in the moved code.
- Make it clearer that bridges are not exposed to userspace.
Reviewed-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160829082757.17913-2-daniel.vetter@ffwll.ch
Same treatment as before. Only hiccup is drm_crtc_mask, which
unfortunately can't be resolved until drm_crtc.h is less of a monster.
Untangle the header loop with a forward declaration for that static
inline.
Reviewed-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160829082757.17913-1-daniel.vetter@ffwll.ch
