Wifi drops, particularly under load

[thedoctar]

On Ubuntu 18.04.3 LTS with Qualcomm Atheros QCA6174 wireless card, internet drops out, particularly when downloading at speeds ~1MB/s say via P2P torrent or ooka speedtest. The wifi connection (at least reported by wicd) remains active, but I cannot ping the router or access the internet. No error message is logged in journalctl after the internet drops. Details on my card, firmware and dmesg given below I'm not the only one with this issue: https://askubuntu.com/questions/1171813/wifi-randomly-or-under-load-disconnects-on-ubuntu-18-04-with-qualcomm-atheros

The issue DOES NOT occur with wired connection (ethernet).
-------------------------------------------------------------------------------------------------
  *-network
       description: Wireless interface
       product: QCA6174 802.11ac Wireless Network Adapter
       vendor: Qualcomm Atheros
       physical id: 0
       bus info: pci@0000:3a:00.0
       logical name: wlp58s0
       version: 32
       serial: 9c:b6:d0:d4:9b:33
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=ath10k_pci driverversion=5.4.0-050400rc8-generic firmware=WLAN.RM.4.4.1-00140-QCARMSWPZ-1 latency=0 link=no multicast=yes wireless=IEEE 802.11

       resources: irq:135 memory:dc000000-dc1fffff
-------------------------------------------------------------------------------------------------
$ dmesg | grep ath10k

[ 2.662000] ath10k_pci 0000:3a:00.0: enabling device (0000 -> 0002)
[ 2.665299] ath10k_pci 0000:3a:00.0: pci irq msi oper_irq_mode 2 irq_mode 0 reset_mode 0
[ 2.950979] ath10k_pci 0000:3a:00.0: qca6174 hw3.2 target 0x05030000 chip_id 0x00340aff sub 1a56:1535
[ 2.950982] ath10k_pci 0000:3a:00.0: kconfig debug 0 debugfs 1 tracing 1 dfs 0 testmode 0
[ 2.951390] ath10k_pci 0000:3a:00.0: firmware ver WLAN.RM.4.4.1-00079-QCARMSWPZ-1 api 6 features wowlan,ignore-otp crc32 fd869beb
[ 3.029754] ath10k_pci 0000:3a:00.0: board_file api 2 bmi_id N/A crc32 4ed3569e
[ 3.108957] ath10k_pci 0000:3a:00.0: unsupported HTC service id: 1536
[ 3.128068] ath10k_pci 0000:3a:00.0: htt-ver 3.47 wmi-op 4 htt-op 3 cal otp max-sta 32 raw 0 hwcrypto 1
[ 3.216750] ath10k_pci 0000:3a:00.0 wlp58s0: renamed from wlan0
[ 3.828149] ath10k_pci 0000:3a:00.0: unsupported HTC service id: 1536
[ 14.519059] ath10k_pci 0000:3a:00.0: unsupported HTC service id: 1536
[ 15.014705] ath10k_pci 0000:3a:00.0: unsupported HTC service id: 1536
[ 1054.860682] ath10k_pci 0000:3a:00.0: unsupported HTC service id: 1536
[ 1055.385335] ath10k_pci 0000:3a:00.0: unsupported HTC service id: 1536

-------------------------------------------------------------------------------------------------
$ dmesg | grep pcieport

[ 0.959817] pcieport 0000:00:1c.0: AER: enabled with IRQ 122
[ 0.960121] pcieport 0000:00:1c.4: AER: enabled with IRQ 123
[ 0.960397] pcieport 0000:00:1c.5: AER: enabled with IRQ 124
[ 0.960657] pcieport 0000:00:1d.0: AER: enabled with IRQ 125
[ 6.644709] pcieport 0000:02:01.0: bridge window [io 0x1000-0x0fff] to [bus 04-38] add_size 1000
[ 6.644711] pcieport 0000:02:02.0: bridge window [io 0x1000-0x0fff] to [bus 39] add_size 1000
[ 6.644713] pcieport 0000:02:02.0: bridge window [mem 0x00100000-0x000fffff 64bit pref] to [bus 39] add_size 200000 add_align 100000
[ 6.644716] pcieport 0000:01:00.0: bridge window [io 0x1000-0x0fff] to [bus 02-39] add_size 3000
[ 6.644719] pcieport 0000:01:00.0: BAR 13: no space for [io size 0x3000]
[ 6.644721] pcieport 0000:01:00.0: BAR 13: failed to assign [io size 0x3000]
[ 6.644723] pcieport 0000:01:00.0: BAR 13: no space for [io size 0x3000]
[ 6.644724] pcieport 0000:01:00.0: BAR 13: failed to assign [io size 0x3000]
[ 6.644728] pcieport 0000:02:02.0: BAR 15: no space for [mem size 0x00200000 64bit pref]
[ 6.644729] pcieport 0000:02:02.0: BAR 15: failed to assign [mem size 0x00200000 64bit pref]
[ 6.644731] pcieport 0000:02:01.0: BAR 13: no space for [io size 0x1000]
[ 6.644732] pcieport 0000:02:01.0: BAR 13: failed to assign [io size 0x1000]
[ 6.644734] pcieport 0000:02:02.0: BAR 13: no space for [io size 0x1000]
[ 6.644735] pcieport 0000:02:02.0: BAR 13: failed to assign [io size 0x1000]
[ 6.644738] pcieport 0000:02:02.0: BAR 15: no space for [mem size 0x00200000 64bit pref]
[ 6.644739] pcieport 0000:02:02.0: BAR 15: failed to assign [mem size 0x00200000 64bit pref]
[ 6.644740] pcieport 0000:02:02.0: BAR 13: no space for [io size 0x1000]
[ 6.644741] pcieport 0000:02:02.0: BAR 13: failed to assign [io size 0x1000]
[ 6.644743] pcieport 0000:02:01.0: BAR 13: no space for [io size 0x1000]
[ 6.644744] pcieport 0000:02:01.0: BAR 13: failed to assign [io size 0x1000]
[ 27.588309] pcieport 0000:02:01.0: bridge window [io 0x1000-0x0fff] to [bus 04-38] add_size 1000
[ 27.588315] pcieport 0000:02:02.0: bridge window [io 0x1000-0x0fff] to [bus 39] add_size 1000
[ 27.588320] pcieport 0000:02:02.0: bridge window [mem 0x00100000-0x000fffff 64bit pref] to [bus 39] add_size 200000 add_align 100000
[ 27.588325] pcieport 0000:01:00.0: bridge window [io 0x1000-0x0fff] to [bus 02-39] add_size 3000
[ 27.588334] pcieport 0000:01:00.0: BAR 13: no space for [io size 0x3000]
[ 27.588337] pcieport 0000:01:00.0: BAR 13: failed to assign [io size 0x3000]
[ 27.588342] pcieport 0000:01:00.0: BAR 13: no space for [io size 0x3000]
[ 27.588344] pcieport 0000:01:00.0: BAR 13: failed to assign [io size 0x3000]
[ 27.588357] pcieport 0000:02:02.0: BAR 15: no space for [mem size 0x00200000 64bit pref]
[ 27.588360] pcieport 0000:02:02.0: BAR 15: failed to assign [mem size 0x00200000 64bit pref]
[ 27.588363] pcieport 0000:02:01.0: BAR 13: no space for [io size 0x1000]
[ 27.588366] pcieport 0000:02:01.0: BAR 13: failed to assign [io size 0x1000]
[ 27.588369] pcieport 0000:02:02.0: BAR 13: no space for [io size 0x1000]
[ 27.588371] pcieport 0000:02:02.0: BAR 13: failed to assign [io size 0x1000]
[ 27.588378] pcieport 0000:02:02.0: BAR 15: no space for [mem size 0x00200000 64bit pref]
[ 27.588381] pcieport 0000:02:02.0: BAR 15: failed to assign [mem size 0x00200000 64bit pref]
[ 27.588384] pcieport 0000:02:02.0: BAR 13: no space for [io size 0x1000]
[ 27.588387] pcieport 0000:02:02.0: BAR 13: failed to assign [io size 0x1000]
[ 27.588390] pcieport 0000:02:01.0: BAR 13: no space for [io size 0x1000]
[ 27.588392] pcieport 0000:02:01.0: BAR 13: failed to assign [io size 0x1000]
[ 31.930841] pcieport 0000:00:1c.0: AER: Corrected error received: 0000:00:1c.0
[ 31.930852] pcieport 0000:00:1c.0: AER: PCIe Bus Error: severity=Corrected, type=Physical Layer, (Receiver ID)
[ 31.930860] pcieport 0000:00:1c.0: AER: device [8086:9d10] error status/mask=00002001/00002000
[ 31.930866] pcieport 0000:00:1c.0: AER: [ 0] RxErr
[ 32.005433] pcieport 0000:02:00.0: Refused to change power state, currently in D3

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-firmware 1.173.13
Uname: Linux 5.4.0-050400rc8-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.9
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Sat Dec 14 00:35:05 2019
Dependencies:

InstallationDate: Installed on 2017-02-26 (1020 days ago)
InstallationMedia: Ubuntu 16.04.2 LTS "Xenial Xerus" - Release amd64 (20170215.2)
PackageArchitecture: all
SourcePackage: linux-firmware
UpgradeStatus: Upgraded to bionic on 2018-10-06 (433 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Lee Blackwell (leeblackwell)]

I'm seeing similar behaviour; the NIC appears to be 'connected' to the AP but no packets appear to move.

root@vs85483:~# lspci | egrep Ath
3b:00.0 Network controller: Qualcomm Atheros QCA6174 802.11ac Wireless Network Adapter (rev 32)
root@vs85483:~#

root@vs85483:~# dmesg | grep ath10k
[ 4.379983] ath10k_pci 0000:3b:00.0: enabling device (0000 -> 0002)
[ 4.384471] ath10k_pci 0000:3b:00.0: pci irq msi oper_irq_mode 2 irq_mode 0 reset_mode 0
[ 4.670211] ath10k_pci 0000:3b:00.0: qca6174 hw3.2 target 0x05030000 chip_id 0x00340aff sub 1a56:1535
[ 4.670213] ath10k_pci 0000:3b:00.0: kconfig debug 0 debugfs 1 tracing 1 dfs 0 testmode 0
[ 4.670611] ath10k_pci 0000:3b:00.0: firmware ver WLAN.RM.4.4.1-00140-QCARMSWPZ-1 api 6 features wowlan,ignore-otp,mfp crc32 29eb8ca1
[ 4.735670] ath10k_pci 0000:3b:00.0: board_file api 2 bmi_id N/A crc32 4ac0889b
[ 4.826897] ath10k_pci 0000:3b:00.0: unsupported HTC service id: 1536
[ 4.846191] ath10k_pci 0000:3b:00.0: htt-ver 3.60 wmi-op 4 htt-op 3 cal otp max-sta 32 raw 0 hwcrypto 1
[ 4.952299] ath10k_pci 0000:3b:00.0 wlp59s0: renamed from wlan0
[ 9.360405] ath10k_pci 0000:3b:00.0: unsupported HTC service id: 1536

root@vs85483:~# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04.2 LTS
Release: 20.04
Codename: focal
root@vs85483:~#

root@vs85483:~# apt list --installed | egrep "^linux-firmware"
[snip]
linux-firmware/focal-updates,focal-updates,now 1.187.12 all [installed,automatic]
root@vs85483:~#

Plucked from lshw:
product: XPS 15 9570 (087C)

System firmware and apt managed packages all up to date as of today (2021/05/20).

I'm happy to assist with further information/tests if that is helpful.

-Lee