Introduction

This page is about debugging 802.11 a/b/g/n/ac WiFi issues. Gathering debugging information is vital for developers to fix wireless driver bugs. This process helps improve the overall quality of wireless drivers.

Debugging information to provide in your report

First, please note "I don't know", "I haven't tested this", "I'll test later", "I'm assuming that...", etc. are not acceptable answers to any of the below. If you don't understand the question, or have to assume something, please advise to what you don't understand or are assuming specifically in your report, and it will be clarified. Otherwise, making such a response will further delay your issue being addressed.

Also, please post in your report both the question and answer, as the presentation of the information here can change:

1. What is the full computer model number (ex. HP G32-301TX Notebook PC)?

2. If you update your BIOS to the newest version following the guide here, does this change anything?

3. Regarding your wireless Access Point (WAP):

   • 3a. What is the current WAP manufacturer, full model, revision, and firmware version?
     3b. If you update the WAP to the latest firmware does it change anything?
     3c. What wireless connection type are you using (802.11ac, 802.11n 150/300, 802.11g, etc.)?
     3d. If you switch to a different wireless type (802.11g or 802.11n if you are using 802.11g) does this change anything?
     3e. What channel specifically are you using when this problem is reproducible?
     3f. In order to understand the wireless environment your WAP is working in, please provide the output of the following terminal command:

     sudo iw dev wlan0 scan | grep -i "ds parameter set"

     3g. What encryption type are you using (ex. WEP, WPA2-PSK, etc.)?
     3h. If you change and remove encryption entirely does this change anything?
     3i. Do you have QoS (Quality of Service)/WMM (Wi-Fi Multimedia) enabled?
     3j. If you disable/enable QoS/WMM does it change anything?
     3k. What is the current beacon interval (usually default is 100)?
     3l. If you adjust this to 50 does it change anything?
     3m. Does your WAP have a firewall enabled?
     3n. If you enable/disable the firewall does it change anything?
     3o. What frequency are you using (2.4GHz, 5GHz, etc.)?
     3p. If you change frequency does it change anything?

4. Does another wireless device tested with the WAP have the same problem as the hardware you initially reported with?
5. What is the distance of the wireless device from the WAP?
6. What is the number and type of obstructions between your device and the WAP?
   • 6a. If you bring the device close to the WAP and eliminate obstructions, does this change anything?
7. Does the issue occur with different WAPs?

8. Is it a regression (i.e. did the problem happen in a prior Ubuntu release)? If so, what release specifically did it last work with? If you do not know, could you please test for this in the earliest release of Ubuntu that is supported as per Ubuntu Releases?

9. Does this problem occur in the newest mainline kernel following https://wiki.ubuntu.com/Kernel/MainlineBuilds? Please mention what specific version of the mainline kernel you tested with in your report.

10. After testing the latest mainline kernel:

    • 10a. If the mainline kernel works, does the development release work? Please mention in your report the specific version you tested.

      10b. If the mainline kernel doesn't work, could you please test compat-wireless from upstream via here and advise to the results?

11. Only for Broadcom wireless chipsets, does the Broadcom STA driver work following https://help.ubuntu.com/community/WifiDocs/Driver/bcm43xx? Please mention what specific version of Broadcom STA you tested with in your report.

12. Only for Realtek wireless chipsets:

    • 12a. Does disabling the firmware power management change anything? This may be done via a terminal:

      sudo nano /etc/modprobe.d/DRIVER.conf

      options DRIVER ips=0 fwlps=0

      where DRIVER is the kernel driver in use for your card found by executing at a terminal:

      lspci -v

      12b. Does the upstream proprietary Realtek driver downloaded from http://www.realtek.com.tw work? Please mention what specific version of the drivers you tested with in your report. If it doesn't work, please contact the card vendor, for example ASUS (not Realtek), file a case number requesting the driver be fixed, and post the case number to your report.

13. Only for Intel wireless chipsets:

    • 13a. Please advise to which firmware version the device is using. Stating the linux-firmware version (ex. apt-cache policy linux-firmware), while necessary, is not the firmware version in use, but the package version of linux-firwmare. In order to find the version in use, one may check dmesg. For example, if the chipset was using the iwlwifi driver:

      cat /var/log/dmesg | grep "firmware version"
      [    2.820714] iwlwifi 0000:03:00.0: loaded firmware version 25.222.9.0 op_mode iwlmvm

      For more on this, please see here.
      13b. Did this work on a prior linux-firmware version? If you don't know, please test a prior release and advise to which version of the firmware, and kernel you tested specifically.
      13c. Does this work, or have a measurable positive impact using the latest firmware available from Intel? If you don't know, please test this with the latest mainline kernel, and firmware available for your chipset.

14. Does ndiswrapper work following https://help.ubuntu.com/community/WifiDocs/Driver/Ndiswrapper? Please mention what specific version of ndiswrapper you tested with, and a link to the Windows driver you used in your report. If ndiswrapper does not work, you are welcome to file a new bug report by executing at a terminal:

    ubuntu-bug ndiswrapper-utils-1.9

Compat-wireless from upstream

Upstream has a more bleeding-edge tree called linux-next, that uses the stable tree as it's base. One would want to test this, as it contains the latest features and fixes, and is a staging area for code that may be merged into Linus's tree. Testing this gives developers vital information on what may fix your issue. For more on this, please see here.

The Ubuntu proposed repository

Keep in mind Ubuntu has a "proposed" repository which allows you to get newer stable kernels (if you are using 2.6.27.10 the proposed repository may have a 2.6.27.14 kernel). Instructions on enabling this repository may be found here. The kernels are propagated over time from the proposed repository to updates over a few weeks period of time after general testing and acceptance.

The Linux wireless guide on reporting bugs

For debugging information preferred by upstream please see: http://wireless.kernel.org/en/users/Documentation/Reporting_bugs