Shared Library Changes for Release 1.3.0


This release contains a handful of changes, none of which affect backward compatibility. Consequently, the libddcutil SONAME ( is unchanged. The full library name is In conformance with Debian practice, the package name is libddcutil4.

API changes

New Function Comments
ddca_enable_sleep_suppression  now a no-op, returns false
ddca_is_sleep_suppression_enabled  always returns false
ddca_force_slave_address  now a non-op, returns false
ddca_is_force_slave_address_enabled  always returns false


  • Function ddca_enable_sleep_suppression() only eliminated sleeps in certain particular situations where the DDC/CI specification is ambiguous. The use of sleeps in these cases has proven unnecessary.
  • Function ddca_force_slave_address() had meaning only when using the i2c-dev write()/read() interface. libddcutil now uses the ioctl() interface exclusively. (But note that use of the write()/read() interface was renabled in release 1.4.0.)
Changed Function Comments
ddca_report_active_displays  show additional information

Notes: ddca_report_active_displays() shows additional information about DRM connection, conflicting drivers.

Miscellaneous Changes

  • library initialization recognizes environment variable DDCUTIL_DEBUG_LIBINIT