Comment 37 for bug 1091372

Hi all,

I am also experiencing constant disconnects on my one week old dell XPS 13 (BIOS A06). I have been trying two different kernels:

- 3.2.0-41-generic #66+kamal16~DellXPS-Ubuntu
- 3.8.0-19.30~precise1

srcversion of the module for the 3.2.0 kernel is
$ modinfo iwlwifi
srcversion: 99F715B156678F68AE86AC4

and for the 3.8.0 kernel:
809985E6954BA6AA05902AC

The two driver versions seem to have different issues, however. The bug in the 3.2. version always reports something about a stuck Queue in dmesg (see bug #1009878 ) while the 3.8. kernel says something described in bug #1159145.

Collecting the information from several forum posts, I always disable 11n mode, hardware encryption and enable the watchdog for stuck queues. I double check these iwlwifi module parameters by cat'ing the corresponding entries in /sys/module/iwlwifi/parameters/. Also I disabled power management for the card by inserting into /etc/pm/power.d/wireless:

#!/bin/sh
/sbin/iwconfig wlan0 power off
exit 0

and checking it with:
$ iwconfig wlan0
wlan0 IEEE 802.11abg ESSID:"Rahi_Net"
          Mode:Managed Frequency:2.412 GHz Access Point: 00:0F:66:24:D9:D9
          Bit Rate=54 Mb/s Tx-Power=15 dBm
          Retry long limit:7 RTS thr:off Fragment thr:off
          Power Management:off
          Link Quality=70/70 Signal level=-38 dBm
          Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
          Tx excessive retries:0 Invalid misc:710 Missed beacon:0

It seems really to be the case, that the 6235 chip from Intel has issues, which are ignored by them. See this forum entry at the Intel support site:
http://communities.intel.com/thread/31090?start=0&tstart=0

A ticket was filed by Red Hat to the linuxwireless bugzilla (official intel development site). As it seems, the buzilla site was taken down "due to security reasons". See bottom of this page:
http://wireless.kernel.org/en/users/Drivers/iwlwifi

Also Dell customers complained without success:
http://en.community.dell.com/techcenter/os-applications/f/4613/t/19464992.aspx?PageIndex=1

It doesn't seem to me, that there will be a solution anytime soon. My question is: does this problem only occur on some XPS 13 notebooks? It seems that the problem with the 6235 chip is very long known, so why did Dell use this chipset in its "Ubuntu Notebook"? And did this really go through QA at Canonical, Dell _and_ Intel? Seems that quite a big number of people are having this issue.

Anyhow I'd like to help, if anyone has questions. The sad thing is, I really don't know how to provoke this bug. Will keep you posted. BTW: does anyone know how I can update the BIOS to A08? The freedos USB boot disk way does not work for me. Running the executable freezes the machine. Also I cannot extract the hdr from the exe.