linux-toradex.git/drivers/gpu/drm/drm_encoder.c, branch v4.19-rc8

drm: Warn if plane/crtc/encoder/connector index exceeds our 32bit bitmasks

2018-01-29T16:46:53+00:00

We use 32bit bitmasks to track planes/crtcs/encoders/connectors.
Naturally we can only do that if the index of those objects stays
below 32. Issue a warning whenever we exceed that limit, hopefully
prompting someone to fix the problem.

For connectors the issue is a bit more complicated as they can
be created/destroyed at runtime due to MST. So the problem is no
longer a purely theoretical programmer error. As the connector
indexes are allocated via ida, we can simply limit the maximum
value the ida is allowed to hand out. The error handling is already
in place.

v2: Return an error to the caller (Harry)
v3: Print a debug message so that we know what happened (Maarten)

Cc: Harry Wentland 
Cc: Maarten Lankhorst 
Cc: Daniel Vetter 
Reviewed-by: Maarten Lankhorst 
Signed-off-by: Ville Syrjälä 
Link: https://patchwork.freedesktop.org/patch/msgid/20180125133020.23845-1-ville.syrjala@linux.intel.com
Reviewed-by: Harry Wentland

drm: Check mode object lease status in all master ioctl paths [v4]

2017-10-25T06:31:30+00:00

Attempts to modify un-leased objects are rejected with an error.
Information returned about unleased objects is modified to make them
appear unusable and/or disconnected.

Changes for v2 as suggested by Daniel Vetter :

 * With the change in the __drm_mode_object_find API to pass the
   file_priv along, we can now centralize most of the lease-based
   access checks in that function.

 * A few places skip that API and require in-line checks.

Changes for v3 provided by Dave Airlie 

 * remove support for leasing encoders.
 * add support for leasing planes.

Changes for v4

 * Only call drm_lease_held if DRIVER_MODESET.

Signed-off-by: Keith Packard 
Signed-off-by: Dave Airlie

drm: Pass struct drm_file * to __drm_mode_object_find [v2]

2017-10-12T00:03:04+00:00

This will allow __drm_mode_object_file to be extended to perform
access control checks based on the file in use.

v2: Also fix up vboxvideo driver in staging

[airlied: merging early as this is an API change]

Suggested-by: Daniel Vetter 
Signed-off-by: Keith Packard 
Signed-off-by: Dave Airlie

drm: Rename connector list iterator API

2017-02-28T15:16:48+00:00

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 
Signed-off-by: Thierry Reding 
Link: http://patchwork.freedesktop.org/patch/msgid/20170228144643.5668-8-thierry.reding@gmail.com

drm: Rename drm_mode_object_get()

2017-02-28T15:14:53+00:00

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 
Acked-by: Christian König 
Signed-off-by: Thierry Reding 
Link: http://patchwork.freedesktop.org/patch/msgid/20170228144643.5668-2-thierry.reding@gmail.com

drm/kms-core: Use recommened kerneldoc for struct member refs

2017-01-25T15:30:34+00:00

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 
Cc: Chris Wilson 
Reviewed-by: Eric Engestrom 
Signed-off-by: Daniel Vetter 
Link: http://patchwork.freedesktop.org/patch/msgid/20170125062657.19270-4-daniel.vetter@ffwll.ch

drm/doc: use preferred struct reference in kernel-doc

2016-12-30T12:34:59+00:00

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 
Cc: Chris Wilson 
Reviewed-by: David Herrmann 
Signed-off-by: Daniel Vetter 
Link: http://patchwork.freedesktop.org/patch/msgid/1483044517-5770-6-git-send-email-daniel.vetter@ffwll.ch

drm: locking&new iterators for connector_list

2016-12-18T13:32:35+00:00

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 
Cc: Chris Wilson 
Reviewed-by: Chris Wilson 
Reviewed-by: Sean Paul 
Signed-off-by: Daniel Vetter 
Link: http://patchwork.freedesktop.org/patch/msgid/20161213230814.19598-6-daniel.vetter@ffwll.ch

drm: bridge: Detach all bridges in a chain at encoder cleanup time

2016-12-18T11:02:49+00:00

Instead of detaching only the bridge directly connected to the encoder,
detach all bridges in the chain.

Signed-off-by: Laurent Pinchart 
Reviewed-by: Daniel Vetter 
Signed-off-by: Archit Taneja 
Link: http://patchwork.freedesktop.org/patch/msgid/1481709550-29226-6-git-send-email-laurent.pinchart+renesas@ideasonboard.com

drm: bridge: Detach bridge from encoder at encoder cleanup time

2016-12-18T11:02:49+00:00

Most drivers that use bridges forgot to detach them at cleanup time.
Instead of fixing them one by one, detach the bridge in the core
drm_encoder_cleanup() function.

Signed-off-by: Laurent Pinchart 
Reviewed-by: Daniel Vetter 
Signed-off-by: Archit Taneja 
Link: http://patchwork.freedesktop.org/patch/msgid/1481709550-29226-5-git-send-email-laurent.pinchart+renesas@ideasonboard.com