Question

I’ve dug into NetworkManager (and from there, into dbus, etc.) and identified the wireless driver I’m using (iwlagn); but I’m sure there’s more I can learn, if I only knew where to look.

Pointers to tutorials, references (on- or off-line), or howtos would be gratefully appreciated.

(If folks feel that this would be better asked on serverfault.com, or superuser.com, just let me know.)

If it’s of interest, here’s what sudo lspci -vvxxx -s 04:0.0 returns:

04:00.0 Network controller: Intel Corporation Wireless WiFi Link 5100
    Subsystem: Intel Corporation Device 1201
    Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
    Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
    Latency: 0, Cache Line Size: 64 bytes
    Interrupt: pin A routed to IRQ 32
    Region 0: Memory at f2c00000 (64-bit, non-prefetchable) [size=8K]
    Capabilities: [c8] Power Management version 3
        Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0+,D1-,D2-,D3hot+,D3cold+)
        Status: D0 PME-Enable- DSel=0 DScale=0 PME-
    Capabilities: [d0] Message Signalled Interrupts: Mask- 64bit+ Queue=0/0 Enable+
        Address: 00000000fee0100c  Data: 41b1
    Capabilities: [e0] Express (v1) Endpoint, MSI 00
        DevCap: MaxPayload 128 bytes, PhantFunc 0, Latency L0s <512ns, L1 unlimited
            ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset+
        DevCtl: Report errors: Correctable- Non-Fatal- Fatal- Unsupported-
            RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+ FLReset-
            MaxPayload 128 bytes, MaxReadReq 128 bytes
        DevSta: CorrErr- UncorrErr- FatalErr- UnsuppReq- AuxPwr+ TransPend-
        LnkCap: Port #0, Speed 2.5GT/s, Width x1, ASPM L0s L1, Latency L0 <128ns, L1 <32us
            ClockPM+ Suprise- LLActRep- BwNot-
        LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- Retrain- CommClk+
            ExtSynch- ClockPM+ AutWidDis- BWInt- AutBWInt-
        LnkSta: Speed 2.5GT/s, Width x1, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
    Capabilities: [100] Advanced Error Reporting <?>
    Capabilities: [140] Device Serial Number 04-ed-3b-ff-ff-65-1e-00
    Kernel driver in use: iwlagn
    Kernel modules: iwlagn
00: 86 80 32 42 06 04 10 00 00 00 80 02 10 00 00 00
10: 04 00 c0 f2 00 00 00 00 00 00 00 00 00 00 00 00
20: 00 00 00 00 00 00 00 00 00 00 00 00 86 80 01 12
30: 00 00 00 00 c8 00 00 00 00 00 00 00 0a 01 00 00
40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
c0: 00 00 00 00 00 00 00 00 01 d0 23 c8 00 00 00 0d
d0: 05 e0 81 00 0c 10 e0 fe 00 00 00 00 b1 41 00 00
e0: 10 00 01 00 c0 8e 00 10 10 08 10 00 11 9c 06 00
f0: 40 01 11 10 00 00 00 00 00 00 00 00 00 00 00 00

Answer 1

First of all, you should enable the debug output of the 802.11 stack in the kernel.

Second, you should compile your kernel (or just the driver module) with debugging output enabled (CONFIG_IWLWIFI_DEBUG). Here’s an excerpt from the Kconfig file:

  To set a value, simply echo an 8-byte hex value to the same file:

      % echo 0x43fff > /sys/class/net/wlan0/device/debug_level

  You can find the list of debug mask values in:
      drivers/net/wireless/iwlwifi/iwl-debug.h

There’s also some DebugFS support for the iwlagn (CONFIG_IWLWIFI_DEBUGFS).

Third, if you’re using WPA or 802.11i (you should), you can kill the NetworkManager and create you’re own config file for the wpa_supplicant (check out the README to see how). Then you can run wpa_supplicant with the -dd switch to turn on its debug info.