apfs/linux-apfs
0
0
Fork 0
mirror of https://github.com/linux-apfs/linux-apfs.git synced 2026-05-01 15:00:59 -07:00
Code Issues Packages Projects Releases Wiki Activity

[media] media: Links setup

Browse Source 
Create the following ioctl and implement it at the media device level to
setup links.

- MEDIA_IOC_SETUP_LINK: Modify the properties of a given link

The only property that can currently be modified is the ENABLED link
flag to enable/disable a link. Links marked with the IMMUTABLE link flag
can not be enabled or disabled.

Enabling or disabling a link has effects on entities' use count. Those
changes are automatically propagated through the graph.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Stanimir Varbanov <svarbanov@mm-sol.com>
Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Laurent Pinchart
2009-12-09 08:40:03 -03:00
committed by Mauro Carvalho Chehab
parent 1651333b09
commit 97548ed4c4
9 changed files with 356 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files
Documentation/media-framework.txt
+42
View File
@@ -259,6 +259,16 @@ When the graph traversal is complete the function will return NULL.
Graph traversal can be interrupted at any moment. No cleanup function call is
required and the graph structure can be freed normally.
Helper functions can be used to find a link between two given pads, or a pad
connected to another pad through an enabled link
media_entity_find_link(struct media_pad *source,
struct media_pad *sink);
media_entity_remote_source(struct media_pad *pad);
Refer to the kerneldoc documentation for more information.
Use count and power handling
----------------------------
@@ -271,3 +281,35 @@ track the number of users of every entity for power management needs.
The use_count field is owned by media drivers and must not be touched by entity
drivers. Access to the field must be protected by the media device graph_mutex
lock.
Links setup
-----------
Link properties can be modified at runtime by calling
media_entity_setup_link(struct media_link *link, u32 flags);
The flags argument contains the requested new link flags.
The only configurable property is the ENABLED link flag to enable/disable a
link. Links marked with the IMMUTABLE link flag can not be enabled or disabled.
When a link is enabled or disabled, the media framework calls the
link_setup operation for the two entities at the source and sink of the link,
in that order. If the second link_setup call fails, another link_setup call is
made on the first entity to restore the original link flags.
Media device drivers can be notified of link setup operations by setting the
media_device::link_notify pointer to a callback function. If provided, the
notification callback will be called before enabling and after disabling
links.
Entity drivers must implement the link_setup operation if any of their links
is non-immutable. The operation must either configure the hardware or store
the configuration information to be applied later.
Link configuration must not have any side effect on other links. If an enabled
link at a sink pad prevents another link at the same pad from being disabled,
the link_setup operation must return -EBUSY and can't implicitly disable the
first enabled link.