Trouble with multiple cards

[Matthew Keeler]

I have been running two QCA9880 based cards for a couple of months now. Recently I needed to update some packages on the router and reboot and ever since I have not been able to get both working again. I have tried downgrading the packages (although none were related to the kernel/driver or the firmware to no avail.

Cards: Airetos AEX-QCA988-NX  
System: Arch Linux with kernel 4.4.5
Firmwares tried: Everything from 10.2.4.70.9-2 through 10.2.4.70.31-2

The symptoms are that upon boot most of the time one of the two cards doesn’t think it can/should transmit on any 5GHz frequency (I haven’t seen the issue with 2.4GHz frequency band). With dmesg I can see two sets of logs about the EEPROM regdomain being 0x0 and it eventually setting my regulatory domain to 0x3a US. iw reg get also confirms that both cards have the right US regulatory domain. One thing which does sometimes clear it up is to "rmmod ath10k_pci ath10k_core && modprobe ath10k_pci”. It doesn’t work every time though.  

So 1) Should 2 ath10k cards coexist properly and 2) Has anyone seen similar behavior and know how to fix it.  


Thanks
Matthew Keeler