5.8. ioctl MEDIA_IOC_SETUP_LINK¶
5.8.1. Name¶
MEDIA_IOC_SETUP_LINK - Modify the properties of a link
5.8.2. Synopsis¶
-
MEDIA_IOC_SETUP_LINK
¶
int ioctl(int fd, MEDIA_IOC_SETUP_LINK, struct media_link_desc *argp)
5.8.3. Arguments¶
fd
File descriptor returned by
open()
.argp
Pointer to struct
media_link_desc
.
5.8.4. Description¶
To change link properties applications fill a struct
media_link_desc
with link identification
information (source and sink pad) and the new requested link flags. They
then call the MEDIA_IOC_SETUP_LINK ioctl with a pointer to that
structure.
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.
Link configuration has no side effect on other links. If an enabled link
at the sink pad prevents the link from being enabled, the driver returns
with an EBUSY
error code.
Only links marked with the DYNAMIC
link flag can be enabled/disabled
while streaming media data. Attempting to enable or disable a streaming
non-dynamic link will return an EBUSY
error code.
If the specified link can’t be found the driver returns with an EINVAL
error code.
5.8.5. Return Value¶
On success 0 is returned, on error -1 and the errno
variable is set
appropriately. The generic error codes are described at the
Generic Error Codes chapter.
- EINVAL
The struct
media_link_desc
references a non-existing link, or the link is immutable and an attempt to modify its configuration was made.