Comment 69 for bug 341952

I experience this locking up on a desktop if I don't blacklist the ath5k module. It's new in Jaunty as well. Whilst it did first appear sometime around Jaunty moving from the beta to the release candidate, I also tried the Ubuntu kernel PPA release of 2.6.30rc4 ( http://kernel.ubuntu.com/~kernel-ppa/mainline/v2.6.30-rc4/ ), but the same issues occur. I'm running no non-free or restricted kernel modules.

Finally, I encountered noise floor calibration issues in dmesg fairly frequently (I didn't save any of the logs to check) - it was akin to what's reported in https://bugzilla.redhat.com/show_bug.cgi?id=452491 however, in particular having that error message ("noise floor calibration timeout") I believe verbatim. It spammed dmesg so much that the boot messages in dmesg were gone within a few hours. However, I don't remember whether this also occurred in the working-(Ubuntu-Jaunty-beta)-kernel or whether its appearance correlates with the hard locks starting.

relevant dpkg output:
ii linux-image-2.6.28-11-generic 2.6.28-11.42 Linux kernel image for version 2.6.28 on x86
ii linux-image-2.6.30-020630rc4-generic 2.6.30-020630rc4 Linux kernel image for version 2.6.30 on x86
ii linux-image-generic 2.6.28.11.15 Generic Linux kernel image
ii linux-restricted-modules-2.6.28-11-generic 2.6.28-11.15 Non-free Linux kernel modules for version 2.
ii linux-restricted-modules-common 2.6.28-11.15 Non-free Linux 2.6.28 modules helper script
ii linux-restricted-modules-generic 2.6.28.11.15 Restricted Linux modules for generic kernels

Abridged lspci information:
05:00.0 Ethernet controller: Atheros Communications Inc. Atheros AR5001X+ Wireless Network Adapter (rev 01)
 Subsystem: Netgear Device 5a00
 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
 Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
 Latency: 64 (2500ns min, 7000ns max), Cache Line Size: 32 bytes
 Interrupt: pin A routed to IRQ 10
 Region 0: Memory at febf0000 (32-bit, non-prefetchable) [size=64K]
 Capabilities: [44] Power Management version 2
  Flags: PMEClk- DSI- D1- D2- AuxCurrent=375mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
  Status: D0 PME-Enable- DSel=0 DScale=2 PME-
 Kernel modules: ath5k