Bugzilla – Bug 1900
Connections deteriorate and start dropping packets after about an hour.
Last modified: 2009-03-08 20:30:02
You need to log in before you can comment on or make changes to this bug.
I'm using Ubuntu 8.10(Intrepid), x86_64 version, fully updated as of 2009/2/7, on a Dell XPS M1710 (Intel core 2 T7200) laptop. I use ssh over our wireless network to connect to our various servers. After about an hour or so, the connection starts dropping packets and very quickly the connection becomes unusable. Restarting ssh etc etc makes no difference. All connections to all servers exhibit the problem. ping shows an average ~ 35% packet loss, but it is very variable. I have now tested with three different routers at two sites and get the same result each time. I am technically adept (programming on linux being my day job) and will be responsive to any debugging/testing suggestions. $ lspci | grep 3945 0c:00.0 Network controller: Intel Corporation PRO/Wireless 3945ABG [Golan] Network Connection (rev 02) $ lsmod | grep iwl iwl3945 112244 0 rfkill 19364 2 iwl3945 mac80211 253440 1 iwl3945 led_class 13192 1 iwl3945 cfg80211 37136 2 iwl3945,mac80211 $ dmesg | grep 3945 [ 13.996611] iwl3945: Intel(R) PRO/Wireless 3945ABG/BG Network Connection driver for Linux, 1.2.26ks [ 13.996614] iwl3945: Copyright(c) 2003-2008 Intel Corporation [ 13.996731] iwl3945 0000:0c:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17 [ 13.996746] iwl3945 0000:0c:00.0: setting latency timer to 64 [ 13.996769] iwl3945: Detected Intel Wireless WiFi Link 3945ABG [ 14.058985] iwl3945: Tunable channels: 13 802.11bg, 23 802.11a channels [ 14.059389] phy0: Selected rate control algorithm 'iwl-3945-rs' [ 14.214557] iwl3945 0000:0c:00.0: PCI INT A disabled [ 26.326844] iwl3945 0000:0c:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17 [ 26.327009] iwl3945 0000:0c:00.0: restoring config space at offset 0x1 (was 0x100102, writing 0x100106) [ 26.329588] firmware: requesting iwlwifi-3945-1.ucode
Please download the latest kernel. Few rate scaling patches have been already applied on latest kernel.
I can also report that since a few months I my download rate falls from 900ko/s to 160ko/s when I download more than 4 files at the same time. I tried doing a ping when I download at 160ko/s and I also noticed 30% packet loss.I can also add that when the connection is deteriated at this point, all the other computer on my wireless network have real poor download speed (roughly 15ko/s), although it should remain more then 700ko/s of bandwith available. The only solution I've found is to deconnect and reconnect from my access point using networkmanager, and I immediatly get back a normal download rate. I'm using Fedora 10 fully updated on a dell latitude d630 with an intel pro/wireless 3945.
Sorry for the new comment, but I forgot to add that I've tried using vista on the same computer or old live-cds (ubuntu 8.04.1 and fedora 8) and I didn't got the problem. I've also tried with another computer under fedora 10 but with a different wireless card and everything worked OK. The main difference I've noticed is in all the other distros working, there was not iwlwifi-3945-2.ucode, so I assume it may be the cause of the problem. I don't want to install testing kernel but if I can help otherwise, just tell me. I don't know what log file to look at to add an attachement.
Romain, This issue is already fixed. You can download the compat-wireless package from here http://wireless.kernel.org/download/compat-wireless-2.6/.
(In reply to comment #4) > Romain, > This issue is already fixed. You can download the compat-wireless package > from here http://wireless.kernel.org/download/compat-wireless-2.6/. > I've tried the compat-wireless-2.6 driver since then and it's much better, but the problem is still there. It just occurs less often. I've tried the 02-05-09 version and the 03-03-09 and the problem occured again.
Can you send me demsg o/p using debug=0x40940002?
Created an attachment (id=1855) [details] The result of dmesg when dowloading with the low rate Here is the results I have when downloading 10 files with a download rate of 160ko/s instead of the 800ko/s I usually have. I'm using the 02-05-09 version of the driver under fedora 10 with the 2.6.27.19-170.2.35.fc10.i686 kernel. It seems to be worst then with the previous kernel: 2.6.27.15-170.2.24.fc10.i686, even though I'm not using the drivers of the kernel. I've also tried the 03-03-09 version and it's the same. I also have the log when everything is ok if you want.
Created an attachment (id=1856) [details] The result of dmesg when dowloading with normal rate
I've gone back to my previous kernel and the bug occurs as fast as in the new kernel. So maybe I was just lucky before. I've look at what was installed/updated with the new kernel: selinux-policy kernel-firmware system-config-date system-config-date-docs selinux-policy-targeted kernel-headers kernel-devel gvfs audit-libs SDL gtkhtml3 evolution-data-server evolution cups-libs mplayer kernel rb_libtorrent rb_libtorrent-python anthy linuxwacom Miro mencoder cups audit audit-libs-python gvfs-gphoto2 gvfs-archive gvfs-obexftp gvfs-smb alsa-utils gvfs-fuse xorg-x11-drv-vmmouse kmod-nvidia-2.6.27.19-170.2.35.fc10.i686 kmod-nvidia evolution-help avidemux-cli evolution-perl avidemux avidemux-gtk I don't see anything that seems related to network, except the new kernel. Now I can reproduce the bug only downloading 2 files at a time!
Created an attachment (id=1858) [details] Rate Scale patch1 Can you check with attached patch and report your finding here.
I've applied the patch to today's tarball and it seems to works fine. I'm downloading multiple files and the download rate is excellent. I'll keep testing but I think that the problem is solved. I'll post again if the problem comes back. Thanks for your hard work.
Closing this bug for now after user's comments.
Created an attachment (id=1862) [details] The result of dmesg when dowloading with the low rate, even with the patch And it's back... It seems that once the bug occurs, even if I disconnect then reconnect to my access point, it gets back pretty quick. I've also tried rebooting my router and the frame rates drops in less than a minute. I should try rebooting my computer.
What band is your AP?
(In reply to comment #14) > What band is your AP? > I don't really understand the question (I'm french). My access point use channel 8 (2.447 GHz). There does not seem to be another access point near mine with the same channel. Was it the question? I've rebooted my computer and it worked for a moment, but the bug is back. It is strange that this afternoon I was able to dowload multiple files during 1h without a problem...
Is is b-band or g-band? When you load the driver are you enabling the debug log? try disabling it. It is really strange, even at my home computer performance increased a lot :-). And I am not able to see any drops.
(In reply to comment #16) > Is is b-band or g-band? When you load the driver are you enabling the debug > log? > try disabling it. > It is really strange, even at my home computer performance increased a lot :-). > And I am not able to see any drops. > It was using both b and g. So I've switch to only g-band. For the moment it seems ok. Was my computer switching from g to b? How comes non of my other computers had this problem? The only time they were affected, it was when my computer was downloading with the crappy rate. At that point, any of my other computers can achieved more than 25ko/s. Maybe it was my AP that can't handle both band at the same time so it switched to b-band whilst my computer was connected. My AP had a firmware update last summer and it's from that moment that I have this problem. I also get disconnected from xbox live after a while since then. So maybe it's the same thing occuring with my xbox... The debug option seems to still be on, even after rebooting. How do I shut it down? Anyway it can't be the cause of the problem since it occured way before I used this debug option. Anyway, I'm still downloading and it's much much better. I hope that this time it's for good. So maybe it wasn't exactly the iwl3945 module after all. But if the patch make your connection better, it wasn't for nothing. :)
Mark it as Verified. Please reopen it if you still see this issue. module options can be found at /etc/modprobe.conf, or files in /etc/modprobe.d. You can search iwl3945 for your options.