osmo-trx rach question

Hi.

I'm troubleshooting peculiar use case with packet access and osmo-bts-trx. There are 2 options for ME to acknowledge reception of control packet to PCU according to 3GPP TS 44.060 § 11.2.2:

1) Packet Control Acknowledgement message

2) 4 identical access bursts

The latter can be both 8-bit RACH and 11-bit RACH (not supported by osmo-bts-trx yet). The choice of response format is defined by OpenBSC in SI: 1) is default, 2) can be activated with "gprs control-ack-type-rach" option.

The problem is that I don't understand how 2) will be handled by OsmoTRX? Shall I expect 4 consecutive RACH messages via rx_rach_fn() in scheduler_trx.c in osmo-bts-trx? Shall it be some other message/function? Will it be ignored/dropped altogether by OsmoTRX?