Comment 3 for bug 581441

I've tried linux-image-2.6.33-02063304-generic and linux-image-2.6.34-020634-generic as well as getting more experience with the standard lucid kernel.
The behaviour of all 3 is closer to the karmic behaviour - perhaps every 1-2 days the wifi system would die with a 'Microcode SW error'. The fix which worked for karmic of disabling wifi, unloading the iwl3945 module, suspending the laptop, waiting 10-20 seconds, resuming the laptop and reloading the iwl3945 module doesn't work as often as it worked with karmic but works more than I first feared.
With linux-image-2.6.33-02063304-generic, there's less log information captured than with karmic. What happens is an error from wpa_supplicant as followsl
May 23 18:35:06 cameron wpa_supplicant[947]: Failed to initiate AP scan.
May 23 18:36:13 cameron wpa_supplicant[947]: last message repeated 6 times
May 23 18:37:13 cameron wpa_supplicant[947]: last message repeated 6 times
May 23 18:38:13 cameron wpa_supplicant[947]: last message repeated 6 times
May 23 18:39:13 cameron wpa_supplicant[947]: last message repeated 6 times
The network connection stays working for some time and doesn't die immediately.
With linux-image-2.6.34-020634-generic, there's more logging information and I've just captured the following.

May 23 17:31:03 cameron kernel: [26917.748945] iwl3945 0000:0c:00.0: Microcode SW error detected. Restarting 0x82000008.
May 23 17:31:03 cameron kernel: [26917.748989] iwl3945 0000:0c:00.0: Start IWL Error Log Dump:
May 23 17:31:03 cameron kernel: [26917.748997] iwl3945 0000:0c:00.0: Status: 0x0002A2E4, count: 1
May 23 17:31:03 cameron kernel: [26917.749004] iwl3945 0000:0c:00.0: Desc Time asrtPC blink2 ilink1 nmiPC Line
May 23 17:31:03 cameron kernel: [26917.749239] iwl3945 0000:0c:00.0: SYSASSERT (#5) 0903237322 0x008B6 0x00274 0x00320 0x007FE 116
May 23 17:31:03 cameron kernel: [26917.749243]
May 23 17:31:03 cameron kernel: [26917.749376] iwl3945 0000:0c:00.0: Start IWL Event Log Dump: display last 20 count
May 23 17:31:03 cameron kernel: [26917.749424] iwl3945 0000:0c:00.0: 09032372300x00000000 0302
May 23 17:31:03 cameron kernel: [26917.749451] iwl3945 0000:0c:00.0: 09032372390x00008000 0350
May 23 17:31:03 cameron kernel: [26917.749479] iwl3945 0000:0c:00.0: 09032372440x000000d9 0106
May 23 17:31:03 cameron kernel: [26917.749507] iwl3945 0000:0c:00.0: 09032372450x00000000 0302
May 23 17:31:03 cameron kernel: [26917.749534] iwl3945 0000:0c:00.0: 09032372540x00008000 0350
May 23 17:31:03 cameron kernel: [26917.749562] iwl3945 0000:0c:00.0: 09032372590x000000d9 0106
May 23 17:31:03 cameron kernel: [26917.749589] iwl3945 0000:0c:00.0: 09032372610x00000000 0302
May 23 17:31:03 cameron kernel: [26917.749617] iwl3945 0000:0c:00.0: 09032372690x00008000 0350
May 23 17:31:03 cameron kernel: [26917.749644] iwl3945 0000:0c:00.0: 09032372740x000000d9 0106
May 23 17:31:03 cameron kernel: [26917.749672] iwl3945 0000:0c:00.0: 09032372760x00000000 0302
May 23 17:31:03 cameron kernel: [26917.749699] iwl3945 0000:0c:00.0: 09032372840x00008000 0350
May 23 17:31:03 cameron kernel: [26917.749727] iwl3945 0000:0c:00.0: 09032372890x000000d9 0106
May 23 17:31:03 cameron kernel: [26917.749754] iwl3945 0000:0c:00.0: 09032372910x00000000 0302
May 23 17:31:03 cameron kernel: [26917.749782] iwl3945 0000:0c:00.0: 09032372990x00008000 0350
May 23 17:31:03 cameron kernel: [26917.749809] iwl3945 0000:0c:00.0: 09032373040x000000d9 0106
May 23 17:31:03 cameron kernel: [26917.749837] iwl3945 0000:0c:00.0: 09032373060x00000000 0302
May 23 17:31:03 cameron kernel: [26917.749865] iwl3945 0000:0c:00.0: 09032373140x00008000 0350
May 23 17:31:03 cameron kernel: [26917.749892] iwl3945 0000:0c:00.0: 09032373190x000000d9 0106
May 23 17:31:03 cameron kernel: [26917.749920] iwl3945 0000:0c:00.0: 09032373200x00000002 0123
May 23 17:31:03 cameron kernel: [26917.749947] iwl3945 0000:0c:00.0: 09032373230x00000100 0125
May 23 17:31:03 cameron kernel: [26917.749977] iwl3945 0000:0c:00.0: Error Reply type 0x00000005 cmd REPLY_TX (0x1C) seq 0x0000 ser 0x00740000
May 23 17:31:03 cameron kernel: [26917.754566] iwl3945 0000:0c:00.0: Can't stop Rx DMA.
May 23 17:31:34 cameron wpa_supplicant[947]: Failed to initiate AP scan.
May 23 17:32:40 cameron wpa_supplicant[947]: last message repeated 6 times
May 23 17:33:40 cameron wpa_supplicant[947]: last message repeated 6 times
May 23 17:34:40 cameron wpa_supplicant[947]: last message repeated 6 times
May 23 17:35:01 cameron wpa_supplicant[947]: last message repeated 2 times

To be clear, there may be more than one problem here. With Karmic, the "Can't stop Rx DMA" error message didn't happen all the times when wifi access died.