struct v4l2_m2m_ops — mem-to-mem device driver callbacks


struct v4l2_m2m_ops {
  void (* device_run) (void *priv);
  int (* job_ready) (void *priv);
  void (* job_abort) (void *priv);
  void (* lock) (void *priv);
  void (* unlock) (void *priv);



required. Begin the actual job (transaction) inside this callback. The job does NOT have to end before this callback returns (and it will be the usual case). When the job finishes, v4l2_m2m_job_finish has to be called.


optional. Should return 0 if the driver does not have a job fully prepared to run yet (i.e. it will not be able to finish a transaction without sleeping). If not provided, it will be assumed that one source and one destination buffer are all that is required for the driver to perform one full transaction. This method may not sleep.


required. Informs the driver that it has to abort the currently running transaction as soon as possible (i.e. as soon as it can stop the device safely; e.g. in the next interrupt handler), even if the transaction would not have been finished by then. After the driver performs the necessary steps, it has to call v4l2_m2m_job_finish (as if the transaction ended normally). This function does not have to (and will usually not) wait until the device enters a state when it can be stopped.


optional. Define a driver's own lock callback, instead of using m2m_ctx->q_lock.


optional. Define a driver's own unlock callback, instead of using m2m_ctx->q_lock.