[FS#253] Multicast over wireless ceases to work properly after a while on ath9k with many clients connected

[LEDE Bugs]

The following task has a new comment added:

FS#253 - Multicast over wireless ceases to work properly after a while on ath9k with many clients connected
User who did this - tofurky (tofurky)

----------
paul, 316-ath9k-fix-more-data-flag-for-buffered-multicast-pack.patch didn't fix the issues i'm having with upnp/ssdp discovery between 2 different ath9k interfaces. i applied it to the compat-wireless in 17.04.4.
fwiw, ssdp discovery works from radio1->eth1, eth1->radio0, and eth1->radio1, but not from radio1->radio0.
radio0, radio1, and eth1 are all members of br-lan. eth0 is wan.
i have igmp_snooping explicitly disabled.
hardware is rspro with 2x AR9280 phy's (radio0 2.4ghz, radio1 5ghz).

----------

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=253#comment3833