rfnoc: Always clear response queue in ctrlport_endpoint

This changes the behaviour of ctrlport_endpoint (the register interface
for block controllers) to always check for an ACK after doing a poke or
poll of any kind. Previously, the behaviour was to only check for an ACK
if the policy was set that way, or if the user requested the ACK to be
received.

The problem with the former approach was that if many pokes were
performed without ever requesting an ACK or a poll, the response queue
would fill up without ever getting emptied, eventually draining the
available heap space. Note that this is not a memory leak in the usual
sense, as the response queue was correctly holding on to the response
packets.

With this change, ctrlport_endpoint::wait_for_ack() now receives
a require_ack parameter. If it is false, the behaviour of wait_for_ack()
is changed as follows:
- If the response queue is empty, immediately return with an empty
  response payload object.
- Otherwise, continue reading elements out of the response queue until
  it is either depleted (in which case the previous rule kicks in), or
  we find the ACK corresponding to the command previously sent out.

Note that this replicates the corresponding behaviour in UHD 3 (see
ctrl_iface_impl::wait_for_ack()).

0 files changed, 0 insertions, 0 deletions