Comment 38 for bug 1629469

I experiencing the same problem, I have Qualcomm Atheros - QCA9565 / AR9565 Wireless Network Adapter. It started after the kernel upgrade, unfortunately, I am not 100% sure which one exactly - most probably 4.4.0-78, and currently I am on 4.4.0-79 and problem still persists. After a day or two of work I have sudden 100% CPU load, and then Wi-Fi failure, which can be cured by the restart only. The messages from the kernel ring buffer are series of these:

[13228.390795] ath: phy0: DMA failed to stop in 10 ms AR_CR=0xffffffff AR_DIAG_SW=0xffffffff DMADBG_7=0xffffffff
[13228.575235] ath: phy0: Chip reset failed
[13228.575236] ath: phy0: Unable to reset channel, reset status -22

After stopping WiFi CPU goes back to normal, but as I said, WiFi driver cannot resume its function and only restart helps.

Also 'lshw -C network' output

  *-network
       description: Wireless interface
       product: QCA9565 / AR9565 Wireless Network Adapter
       vendor: Qualcomm Atheros
       physical id: 0
       bus info: pci@0000:04:00.0
       logical name: wlan0
       version: 01
       serial: dc:85:de:f8:f1:d1
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress cap_list rom ethernet physical wireless
       configuration: broadcast=yes driver=ath9k driverversion=4.4.0-79-generic firmware=N/A latency=0 link=no multicast=yes wireless=IEEE 802.11bgn
       resources: irq:10 memory:f7900000-f797ffff memory:f7980000-f798ffff
  *-network
       description: Ethernet interface
       product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0.1
       bus info: pci@0000:05:00.1
       logical name: eth0
       version: 12
       serial: 1c:b7:2c:24:c5:cc
       size: 100Mbit/s
       capacity: 1Gbit/s
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl8411-2_0.0.1 07/08/13 ip=192.168.0.103 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s
       resources: irq:10 ioport:d000(size=256) memory:f7814000-f7814fff memory:f7810000-f7813fff