ath10k-regression in 4.14: Connections aborts with "failed to extract amsdu: -11"

[Thorsten Leemhuis]

Lo! The wifi connection of my Dell XPS13 (9360) with its QCA6174
sometimes suddenly stops working since I switched to 4.14-rc2+. Every
time it happens, there is this error message in dmesg:

> ath10k_pci 0000:3a:00.0: failed to extract amsdu: -11

I have to switch wifi off and on with the hotkey to reconnect. I can
trigger the aborts by starting a big download and waiting a few minutes.
Sometimes the connections aborts during normal load. Installing the
latest firmware didn't help. The wifi works just fine with 4.13.3. While
investigating this I noticed a few messages in dmesg that only appear in
4.14-rc (I used 35dbba31be52):

> ath10k_pci 0000:3a:00.0: Direct firmware load for ath10k/pre-cal-pci-0000:3a:00.0.bin failed with error -2
> ath10k_pci 0000:3a:00.0: Direct firmware load for ath10k/cal-pci-0000:3a:00.0.bin failed with error -2

Do they have anything to do with this? Hardware is

> 3a:00.0 Network controller [0280]: Qualcomm Atheros QCA6174 802.11ac Wireless Network Adapter [168c:003e] (rev 32)
Wifi Firmware:

> firmware ver WLAN.RM.4.4.1-00026-QCARMSWP-1 api 6 features wowlan,ignore-otp,raw-mode crc32 7b90c3fc
> board_file api 2 bmi_id N/A crc32 414716a3

Should I try to bisect this or is this issue already known? Side note
FYI: I also updated the BIOS of the XPS13 recently (but there is a newer
one available that I haven't installed yet) and switched to a newer
Fedora version, but that afaics hasn't anything to do with this, as 4.13
works just fine (famous last words...)

Ciao, Thorsten

P.S.: full dmesg output:
http://www.leemhuis.info/files/misc/dmesg-ath10k-problem-4.14-rc
Kernel config based on Fedora rawhide