tree 24fba539288862ce25feebae730a564fd576fbcc
parent fc464935a451346a24150d60e62f84d42022f910
author Pau Espin Pedrol <pespin@sysmocom.de> 1611592231 +0100
committer Pau Espin Pedrol <pespin@sysmocom.de> 1611674794 +0100

sched: Avoid picking TBF with nacked dl blocks when GMSK is required

Sine we don't yet implement properly all resegmentation of blocks from
same MCS family type, when requiring a GMSK DL block (due to GPRS+EGPRS
multiplexing limitations) we need to skip retransmitions, otherwise we'd
be incorrectly picking a DL block which was already built with a
potentially higher MCS value.

The "DL_PRIO_NEW_DATA" prio serves two purposes:
* There's new data to send
* There's some nacked data to be retransmitted

The 2nd purpose has, later on, more priority over the 1st one when the tbf
is selected (see gprs_rlcmac_dl_tbf::take_next_bsn()).

Until now we were handling correctly the case where the tbf was skipped
in case the prio was to resend unacked data (DL_PRIO_SENT_DATA), but
was incorrectly selected when it'd send nacked data. Let's fix it by
specifically checking w->resend_needed() < 0.

Change-Id: I253de8e1a190a9adb56160f38892c9e43e2c0272