Kernel 4.15.0-39.42 not compatible with Qualcomm Atheros QCA9377

[mxCoder]

Yesterday I got upgrades including kernel 4.15.0-39, this morning when I booted my laptop I was unable to connect or see any wifi networks, under closer inspection the whole wireless networking UI was disabled.

lshw was not showing my wireless adapter.

Rebooted with 4.15.0-38 and now everything works correctly.

lshw shows

  *-network
       description: Wireless interface
       product: QCA9377 802.11ac Wireless Network Adapter
       vendor: Qualcomm Atheros
       physical id: 0
       bus info: pci@0000:03:00.0
       logical name: wlp3s0
       version: 31
       serial: 74:40:bb:a8:4a:a7
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=ath10k_pci driverversion=4.15.0-38-generic firmware=WLAN.TF.1.0-00002-QCATFSWPZ-5 ip=192.168.1.74 latency=0 link=yes multicast=yes wireless=IEEE 802.11
       resources: irq:131 memory:d2000000-d21fffff

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-4.15.0-38-generic 4.15.0-38.41
ProcVersionSignature: Ubuntu 4.15.0-38.41-generic 4.15.18
Uname: Linux 4.15.0-38-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: ricardoe 2674 F.... pulseaudio
CurrentDesktop: MATE
Date: Wed Nov 14 09:31:20 2018
InstallationDate: Installed on 2018-10-05 (40 days ago)
InstallationMedia: Ubuntu-MATE 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
MachineType: Dell Inc. Inspiron 5570
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-38-generic root=UUID=aa7aabab-0040-44e5-a647-26ffb4729da5 ro quiet splash vt.handoff=1
RelatedPackageVersions:
 linux-restricted-modules-4.15.0-38-generic N/A
 linux-backports-modules-4.15.0-38-generic N/A
 linux-firmware 1.173.1
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 08/15/2018
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.1.8
dmi.board.name: 0Y1T82
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 10
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvr1.1.8:bd08/15/2018:svnDellInc.:pnInspiron5570:pvr:rvnDellInc.:rn0Y1T82:rvrA00:cvnDellInc.:ct10:cvr:
dmi.product.family: Inspiron
dmi.product.name: Inspiron 5570
dmi.sys.vendor: Dell Inc.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[Joseph Salisbury (jsalisbury)]

There are only 50 commits between Ubuntu-4.15.0-38 and Ubuntu-4.15.0-39, so it should be easy to track down. I'll review the commit log. If nothing sticks out we can perform a kernel bisect to identify the offending commit.

[Joseph Salisbury (jsalisbury)]

Nothing sticks out in that range of commits. There is nothing atheros related. Before starting a bisect, can you confirm -proposed does not already fix the bug?

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed.

Thank you in advance!

[Joseph Salisbury (jsalisbury)]

I also started a kernel bisect between Ubuntu-4.15.0-38 and Ubuntu-4.15.0-39. The kernel bisect will require testing of about 7-10 test kernels.

I built the first test kernel, up to the following commit:
125291b1852e43501135f787adf03fa590e33f59

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1803392

If -proposed still exhibits the bug, can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance