iwn panic from Wireless-N 2200

[Michael Zhilin]

Hi,

Since yesterday I see constant errors from wireless card Wireless-N 2200 on
FreeBSD 12-ALPHA3 (sorry, not yet updated to 13-CURRENT):
iwn0: iwn_panicked: controller panicked, iv_state = 0; restarting
iwn0: iwn_intr: fatal firmware error
firmware error log:
error type = "UNKNOWN" (0x00000066)
program counter = 0x00010CD4
source line = 0x00027212
error data = 0x0000000103030000
branch link = 0x00010CA200010D14
interrupt link = 0x0000E1AE0000E1AE
time = 3671208223
driver status:
tx ring 0: qid=0 cur=222 queued=0
tx ring 1: qid=1 cur=4 queued=0
tx ring 2: qid=2 cur=4 queued=0
tx ring 3: qid=3 cur=7 queued=1
tx ring 4: qid=4 cur=0 queued=0
tx ring 5: qid=5 cur=0 queued=0
tx ring 6: qid=6 cur=0 queued=0
tx ring 7: qid=7 cur=0 queued=0
tx ring 8: qid=8 cur=0 queued=0
tx ring 9: qid=9 cur=96 queued=0
tx ring 10: qid=10 cur=0 queued=0
tx ring 11: qid=11 cur=0 queued=0
tx ring 12: qid=12 cur=0 queued=0
tx ring 13: qid=13 cur=0 queued=0
tx ring 14: qid=14 cur=0 queued=0
tx ring 15: qid=15 cur=0 queued=0
tx ring 16: qid=16 cur=75 queued=1
tx ring 17: qid=17 cur=0 queued=0
tx ring 18: qid=18 cur=0 queued=0
tx ring 19: qid=19 cur=0 queued=0
rx ring: cur=19
iwn0: iwn_panicked: controller panicked, iv_state = 0; restarting
iwn0: iwn_read_firmware: ucode rev=0x12a80601

It looks like microcode stopped processing due to internal error.
I wonder if it's known issue and if no, how to troubleshoot it.

Thank you in advance!