Sam Hooke

These are rough notes from whatever I was working on, interested in or thinking about at the time. They vary greatly in quality and length, but prove useful to me, and hopefully to you too!

Troubleshooting wifi driver crashing (part 2)

Going to attempt upgrading to a more recent iwlwifi firmware version to see if that fixes my wifi issues. Using the Debian testing distribution instead of stable allows me to upgrade from iwlwifi -22 to -29:

$ sudo apt install firmware-iwlwifi -t testing
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages will be upgraded:
  firmware-iwlwifi
1 upgraded, 0 newly installed, 0 to remove and 1378 not upgraded.
Need to get 5,027 kB of archives.
After this operation, 6,874 kB disk space will be freed.
Get:1 http://ftp.uk.debian.org/debian testing/non-free amd64 firmware-iwlwifi all 20180825+dfsg-1 [5,027 kB]
Fetched 5,027 kB in 0s (5,630 kB/s)           
Reading changelogs... Done
(Reading database ... 145072 files and directories currently installed.)
Preparing to unpack .../firmware-iwlwifi_20180825+dfsg-1_all.deb ...
Unpacking firmware-iwlwifi (20180825+dfsg-1) over (20161130-3) ...
Setting up firmware-iwlwifi (20180825+dfsg-1) ...
$ ls -al /lib/firmware | grep 7265
-rw-r--r--  1 root root 1180412 Aug 29 21:14 iwlwifi-7265-17.ucode
-rw-r--r--  1 root root  697828 Aug 29 21:14 iwlwifi-7265-9.ucode
-rw-r--r--  1 root root 1028376 Aug 29 21:14 iwlwifi-7265D-22.ucode
-rw-r--r--  1 root root 1036432 Aug 29 21:14 iwlwifi-7265D-29.ucode

Even though the above shows that the new firmware is installed, it does not appear to be being used, even after a reboot:

$ sudo modinfo iwlwifi | grep "\-26"
firmware:       iwlwifi-7265D-26.ucode
firmware:       iwlwifi-3168-26.ucode
firmware:       iwlwifi-8265-26.ucode
firmware:       iwlwifi-8000C-26.ucode
firmware:       iwlwifi-9000-pu-a0-lc-a0--26.ucode
firmware:       iwlwifi-9260-th-a0-jf-a0--26.ucode
firmware:       iwlwifi-9000-pu-a0-jf-a0--26.ucode
firmware:       iwlwifi-Qu-a0-jf-b0--26.ucode
sam@cpe1704tks:~$ sudo modinfo iwlwifi | grep "\-29"

(Note how grepping for -26 finds a firmware, but -29 returns nothing).

Also note how dmesg shows that the kernel starts searching at 26 and counts down, even though 29 is present in /lib/firmware:

$ sudo dmesg | grep 7265D
[    2.560711] iwlwifi 0000:02:00.0: firmware: failed to load iwlwifi-7265D-26.ucode (-2)
[    2.560809] iwlwifi 0000:02:00.0: Direct firmware load for iwlwifi-7265D-26.ucode failed with error -2
[    2.560838] iwlwifi 0000:02:00.0: firmware: failed to load iwlwifi-7265D-25.ucode (-2)
[    2.560926] iwlwifi 0000:02:00.0: Direct firmware load for iwlwifi-7265D-25.ucode failed with error -2
[    2.560949] iwlwifi 0000:02:00.0: firmware: failed to load iwlwifi-7265D-24.ucode (-2)
[    2.561034] iwlwifi 0000:02:00.0: Direct firmware load for iwlwifi-7265D-24.ucode failed with error -2
[    2.561056] iwlwifi 0000:02:00.0: firmware: failed to load iwlwifi-7265D-23.ucode (-2)
[    2.561134] iwlwifi 0000:02:00.0: Direct firmware load for iwlwifi-7265D-23.ucode failed with error -2
[    2.598990] iwlwifi 0000:02:00.0: firmware: direct-loading firmware iwlwifi-7265D-22.ucode

This behaviour is perhaps because the iwlwifi driver chooses which firmware to load based upon the kernel version.

My kernel version is 4.9.0:

$ uname -r
4.9.0-8-amd64

My wifi chipset is a 7265D. The last version of iwlwifi to support the 7265D is v29. A 7265D device can be distringuished from a plain old 7265 (without D) in dmesg by the presence of 0x210 in this line:

Detected Intel(R) Dual Band Wireless AC 7265, REV=0x210

Going to manually install.

First download the drivers from the website. I chose iwlwifi-7265-ucode-16.242414.0.tgz because it is for kernels v4.3+ (mine is v4.9.0) and it is compatible with the 7265 chipset (no mention of 7265D, but hopefully this is the right one).

Then remove the iwlwifi driver installed through apt:

$ 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, 39.8 MB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 145066 files and directories currently installed.)
Removing firmware-iwlwifi (20180825+dfsg-1) ...

Extracting the .tgz file reveals it does contain the 7265D firmware, and a rather helpful README file!

$ ls -l
total 2524
-rw-rw-r-- 1 sam sam 1180356 Dec 23  2015 iwlwifi-7265-16.ucode
-rw-rw-r-- 1 sam sam 1384500 Dec 23  2015 iwlwifi-7265D-16.ucode
-rw-r--r-- 1 sam sam    2041 Dec 29  2013 LICENSE.iwlwifi-7265-ucode
-rw-r--r-- 1 sam sam    4899 Dec 23  2015 README.iwlwifi-7265-ucode

Following the instructions I install the firmware manually:

$ sudo cp iwlwifi-7265D-16.ucode /lib/firmware/

Now let’s reboot and see if I am now using -16


The kernel only searched from -26 to -22 so I am now without wifi again. I must have chosen the wrong version.

As a hack, let’s try seeing what happens if we trick it into loading the -16 firmware:

$ cd /lib/firmware
sudo mv iwlwifi-7265D-16.ucode iwlwifi-7265D-26.ucode 

And now let’s reboot again…


Perhaps no surprise, it did not like the hack:

[    2.322343] iwlwifi 0000:02:00.0: firmware: direct-loading firmware iwlwifi-7265D-26.ucode
[    2.322364] iwlwifi 0000:02:00.0: Driver unable to support your firmware API. Driver supports v26, firmware is v16.
[    2.322595] iwlwifi 0000:02:00.0: firmware: failed to load iwlwifi-7265D-25.ucode (-2)
[    2.322685] iwlwifi 0000:02:00.0: Direct firmware load for iwlwifi-7265D-25.ucode failed with error -2
[    2.322709] iwlwifi 0000:02:00.0: firmware: failed to load iwlwifi-7265D-24.ucode (-2)
[    2.322795] iwlwifi 0000:02:00.0: Direct firmware load for iwlwifi-7265D-24.ucode failed with error -2
[    2.322823] iwlwifi 0000:02:00.0: firmware: failed to load iwlwifi-7265D-23.ucode (-2)
[    2.322906] iwlwifi 0000:02:00.0: Direct firmware load for iwlwifi-7265D-23.ucode failed with error -2
[    2.322929] iwlwifi 0000:02:00.0: firmware: failed to load iwlwifi-7265D-22.ucode (-2)
[    2.323012] iwlwifi 0000:02:00.0: Direct firmware load for iwlwifi-7265D-22.ucode failed with error -2

Dodgy wifi is better than no wifi, so let’s reinstall the old firmware which has the issue. Fortunately aptitude has a local cache so I can reinstall firmware-iwlwifi without any internet:

sudo apt install firmware-iwlwifi

Now let’s try a different approach. We’ll change the iwlwifi configuration a bit, specifically to disable power saving amongst other things:

$ cat /etc/modprobe.d/iwlwifi.conf 
options iwlwifi bt_coex_active=0 swcrypto=0 11n_disable=8 power_save=0

Let’s leave it at that for now and see if it helps.


All articles in this series:

<< Previous: Install Hugo testing distribution on Debian
Next: Holiday to Italy visiting Pompeii, Herculaneum, Vesuvius and the Amalfi Coast >>