rtl8812au-dkms 4.3.8.12175.20140902+dfsg-0ubuntu2: rtl8812au kernel module failed to build [/lib/modules/3.13.0-77-generic/build: No such file or directory. Stop.]

[Randy Bass]

TP-Link T4u WIFI USB NIC worked fine for Xubuntu kernels up to 3.13.0-77 (LTS 14.04) with driver r8812au. After that, it will not work. Even with upgrade to 4.4.0-34 (LTS 16.04), WIFI still does not work. Prior to upgrade, if I booted into kernel 3.13.0-77, it worked fine. Now after upgrade, WIFI will not work even when I revert to kernel 13.3.0-77. This bug report was generated when I went into Software and Updates -> Additional Drivers (from kernel 3.13.0-77). The device was listed as "Unknown: Unknown" with radio button "Do not use the device" selected. I tried to change that to "Using dkms source for the r8812au network driver from rtl8812au-dkms (open source)" which resulted in this automated bug report.

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: rtl8812au-dkms 4.3.8.12175.20140902+dfsg-0ubuntu2
ProcVersionSignature: Ubuntu 3.13.0-77.121-generic 3.13.11-ckt32
Uname: Linux 3.13.0-77-generic i686
NonfreeKernelModules: nvidia
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: i386
DKMSKernelVersion: 4.4.0-34-generic
Date: Tue Aug 16 10:49:39 2016
InstallationDate: Installed on 2015-02-06 (557 days ago)
InstallationMedia: Xubuntu 14.04.1 LTS "Trusty Tahr" - Release i386 (20140723)
PackageArchitecture: all
PackageVersion: 4.3.8.12175.20140902+dfsg-0ubuntu2
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.1
 apt 1.2.12~ubuntu16.04.1
SourcePackage: rtl8812au
Title: rtl8812au-dkms 4.3.8.12175.20140902+dfsg-0ubuntu2: rtl8812au kernel module failed to build
UpgradeStatus: Upgraded to xenial on 2016-08-16 (0 days ago)

[Launchpad Janitor (janitor)]

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

[Jeremy (wa113y3s)]

I think line 4 in the dkms.conf file needs to be changed from

MAKE="'make' all"

to

MAKE="'make' all KVER=${kernelver}"

for the package to work correctly as it is building against the old kernel source instead of the new

[Randyman99 (rgb99)]

Thanks for the suggestion, Jeremey, however, I didn't find the need to implement it. With the most recent update to kernel 4.4.0-38, it is working correctly now automatically, with no effort or changes on my part. I can run

    Modinfo 8812au

And inspect the line

    vermagic: 4.4.0-38-generic SMP mod_unload modversions 686

which shows that it was recompiled for the latest kernel when the kernel was installed. On the basis of one kernel update, I'm optimistic.

[Randy Bass (randybass)]

Jeremey, actually, I'm not sure, but I think the Ubuntu update was compiling the module after downloading the new kernel before the system was rebooted into the new kernel, which is how the module was compiled for the old kernel instead of the new. On rebooting, I was unable to rebuild the module for the new kernel, as it said the module was already installed. Using "modprobe -r <modname>" doesn't work because the module is installed by dmks. I had to issue the command

sudo dkms remove -m 8812au -v 1.0 -k <kernel>

to remove it. Without the kernel specified, I think it will delete module builds for all kernel versions, which means you won't be able to boot into an older kernel and have the wifi work.

Then I was able to rebuild the module from the current (latest) kernel version and install it with dkms, and everything worked fine:

    sudo dkms add -m 8812au -v 1.0
    sudo dkms build -m 8812au -v 1.0
    sudo dkms install -m 8812au -v 1.0

 As I said in my last post however, with the most recent update to kernel 4.4.0-38, the build happened automatically and this wasn't necessary. I'm optimistic the bug could be fixed.