Sam Hooke

Troubleshooting wifi driver crashing (part 3)

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We’re going to try and downgrade iwlwifi from version -22 to -17, roughly following advice from here.

This person also has trouble with the -22 version:

Other people reported problems with the -21 version:

Okay, first stop apt from trying to upgrade this package:

sudo apt-mark hold firmware-iwlwifi

Then remove the -22 and -21 version. This should force the kernel to load the previous version which is -17 from what I can see in /lib/firmware/.

sudo mv /lib/firmware/iwlwifi-7265D-22.ucode .
sudo mv /lib/firmware/iwlwifi-7265D-21.ucode .

Time to reboot…

That… did not work. The drivers failed to load, and it did not attempt -17:

[    2.580420] iwlwifi 0000:02:00.0: firmware: failed to load iwlwifi-7265D-26.ucode (-2)
[    2.580521] iwlwifi 0000:02:00.0: Direct firmware load for iwlwifi-7265D-26.ucode failed with error -2
[    2.580562] iwlwifi 0000:02:00.0: firmware: failed to load iwlwifi-7265D-25.ucode (-2)
[    2.580644] iwlwifi 0000:02:00.0: Direct firmware load for iwlwifi-7265D-25.ucode failed with error -2
[    2.580668] iwlwifi 0000:02:00.0: firmware: failed to load iwlwifi-7265D-24.ucode (-2)
[    2.580748] iwlwifi 0000:02:00.0: Direct firmware load for iwlwifi-7265D-24.ucode failed with error -2
[    2.580770] iwlwifi 0000:02:00.0: firmware: failed to load iwlwifi-7265D-23.ucode (-2)
[    2.580826] iwlwifi 0000:02:00.0: Direct firmware load for iwlwifi-7265D-23.ucode failed with error -2
[    2.580840] iwlwifi 0000:02:00.0: firmware: failed to load iwlwifi-7265D-22.ucode (-2)
[    2.580889] iwlwifi 0000:02:00.0: Direct firmware load for iwlwifi-7265D-22.ucode failed with error -2

Networking broke completely:

$ ping 8.8.8.8
connect: Network is unreachable

Let’s mv the firmware back in place and reboot…

This time let’s try removing the firmware-iwlwifi package which we got from apt, and instead download the firmware ourselves and install it manually.

$ sudo apt-mark unhold firmware-iwlwifi
$ sudo apt remove firmware-iwlwifi
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages will be REMOVED:
  firmware-iwlwifi
0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
After this operation, 46.7 MB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 145071 files and directories currently installed.)
Removing firmware-iwlwifi (20161130-3) ...

Download iwlwifi-7265-ucode-25.30.13.0.tgz (version -13) from here.

Follow instructions in README…

After reboot it was just ignored by the kernel. The kernel seems to only be trying to load from -26 to -22?

Let’s see what happens if we rename the -13 firmware to -26 to trick the kernel into trying to load it:

[  127.719341] iwlwifi 0000:02:00.0: firmware: direct-loading firmware iwlwifi-7265D-26.ucode
[  127.719361] iwlwifi 0000:02:00.0: Driver unable to support your firmware API. Driver supports v26, firmware is v13.

Okay, let’s reset back to normal and re-install firmware-iwlwifi from apt:

sudo apt install firmware-iwlwifi

Now let’s try and get -21 to be loaded instead of -22 by renaming it to -26 so that the kernel tries to load it first:

sudo mv /lib/firmware/iwlwifi-7265D-21.ucode /lib/firmware/iwlwifi-7265D-26.ucode

And rather than rebooting again, we can use modprobe to trigger the loading:

$ sudo modprobe -r iwlwifi
sam@cpe1704tks:~$ sudo modprobe iwlwifi
sam@cpe1704tks:~$ sudo dmesg | grep iwlwifi
...snip...
[  462.138715] iwlwifi 0000:02:00.0: firmware: direct-loading firmware iwlwifi-7265D-22.ucode
[  462.139142] iwlwifi 0000:02:00.0: loaded firmware version 22.361476.0 op_mode iwlmvm
[  462.174085] iwlwifi 0000:02:00.0: Detected Intel(R) Dual Band Wireless AC 7265, REV=0x210
[  462.176442] iwlwifi 0000:02:00.0: L1 Enabled - LTR Enabled
[  462.176994] iwlwifi 0000:02:00.0: L1 Enabled - LTR Enabled
[  462.259519] iwlwifi 0000:02:00.0 wlp2s0: renamed from wlan0
[  462.291123] iwlwifi 0000:02:00.0: L1 Enabled - LTR Enabled
[  462.291582] iwlwifi 0000:02:00.0: L1 Enabled - LTR Enabled
[  462.357429] iwlwifi 0000:02:00.0: L1 Enabled - LTR Enabled
[  462.357881] iwlwifi 0000:02:00.0: L1 Enabled - LTR Enabled
[  462.390375] iwlwifi 0000:02:00.0: L1 Enabled - LTR Enabled
[  462.390925] iwlwifi 0000:02:00.0: L1 Enabled - LTR Enabled
[  462.457893] iwlwifi 0000:02:00.0: L1 Enabled - LTR Enabled
[  462.458443] iwlwifi 0000:02:00.0: L1 Enabled - LTR Enabled

That did not work. It failed on the -21 discused as -26 and continued on down to successfully load -22.

I give up.

Let’s take a different approach and instead buy a FSF-certified USB wifi adapter.

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