Bug 16132
| Summary: | [iwl3945] Sudden drop of transfer rate | ||
|---|---|---|---|
| Product: | Networking | Reporter: | Andrey Zhekov (_apj) |
| Component: | Wireless | Assignee: | Stanislaw Gruszka (stf_xl) |
| Status: | RESOLVED OBSOLETE | ||
| Severity: | high | CC: | alan, erappleman, linville, qbast, reinette.chatre, stf_xl, thsundel, wey-yi.w.guy |
| Priority: | P1 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Kernel Version: | 2.6.38 | Subsystem: | |
| Regression: | Yes | Bisected commit-id: | |
|
Description
Andrey Zhekov
2010-06-05 19:26:28 UTC
I read through the comments in the link you provided and things seem to be very inconclusive. For a start people using wireless devices from various vendors are complaining that their speed dropped after updating Ubuntu. Some report that the default install worked well but some update afterward caused things to slow down. It is not possible for me to reliably debug kernels that are unique to OSV since they make changes to it that are not available in the general releases. To get an idea of what the issue is, could you try a recent vanilla kernel? If you do not want to update your entire kernel then you can use compat-wireless. The ideal would probably be if you can try out the latest code by testing the latest compat-wireless, see http://wireless.kernel.org/en/users/Download Hello I tried the link you provided (http://wireless.kernel.org/en/users/Download) after that I totaly loose wifi connection even when all modules from the archive were loaded. So, I decided to look at the problem by another way. In the Launchpad report I said that the issue exist on Archlinux too with the same kernel of 2.6.32.X series. Now I'm using Ubuntu as a test mahine. The symptom of the issue is as following: - after login I'm notified about avaiable updates for the system and start to download them. The speed is great as it has to be (~700Kbytes/sec). But after 40sec-to-1 minute or so the speed becomes around 80-120KBytes and never goes back to nominal 700. At the moment I have Ubuntu kernel 2.6.32-23-generic-pae and recently I tried mainline kernel 2.6.35rc2 - had the same result If I can help somehow with troubleshooting - please tell me Thanks in advance! Andrey I can confirm this bug on Ubuntu Maverick with a 3945. Linux kingfisher 2.6.35-22-generic #33-Ubuntu SMP Sun Sep 19 20:34:50 UTC 2010 i686 GNU/Linux Using ndiswrapper instead of iwl3945, I get full speeds with no drop in speed. BTW, if you need more data on this bug... http://bugzilla.intellinuxwireless.org/show_bug.cgi?id=1592 http://bugzilla.intellinuxwireless.org/show_bug.cgi?id=1932 https://bugs.launchpad.net/ubuntu/+source/linux/+bug/340418 hi, we are aware of this issue. but currently we are focus and busy on issues with our new product release. We will do our best to address any issues on our legacy products as soon as we have time. sorry and thanks for reporting. Wey Not to be rude, but I really find that unacceptable given how this bug has been around ever since ipw3945 was deprecated. That is, it's been plaguing Ubuntu for 6 releases, Maverick included. When we decided to move to Linux we thought that the perfect hardware for our laptops would be computers with as much of intel hw as possible, since we though you guys loved Linux and opensource in general. Now we have updated our Linux distro to the newest version and hundreds of our laptops suffers this slow wlan bug, I'm very popular now with my users, thanks Intel! Linux motto is not "use and throw away", Linux is expected to run great even on "legacy" HW!! I hoped this motto would also be yours (Intel). Max speeds over time using Live USB sessions Gutsy (ipw3945): 24 Mbps Karmic (iwl3945): 16 Mbps Lucid (iwl3945): 16 Mbps Maverick (iwl3945): 1-3 Mbps Natty (iwl3945): 1-3 Mbps Natty (ndiswrapper): 24 Mbps https://bugs.launchpad.net/ubuntu/+source/linux/+bug/621265 It's a nasty bug that affects at least the latest Ubuntu, Mint and Fedora. It also affects vanilla kernels compiled in these distros. Still, I couldn't reproduce it in Gentoo. The bug still exists in 2.6.37, 2.6.38 and 3.0-rc7. Tested on Fujitsu Siemens v5505 with OpenSUSE. Download speed is about 1-1.5Mbit/s. The same machine gets 6Mbit/s (the same as wired connection) under Windows. If anybody actually cares about this bug and needs more info, I will be happy to perform whatever tests are necessary. Could you look here? https://bugzilla.redhat.com/show_bug.cgi?id=671366 It's the thread where mine problem got solved. According to this thread, Fedora kernel kernel-2.6.38.4-20.fc15 should have this problem fixed. I installed 2.6.38.8-35.fc15.i686, but the speed is still only 1.2Mbit/s. I also found old Fedora 9 live with kernel 2.6.25 - speed was also slow. I see that your last comment in that thread was #54 - "did not help me either". So what exactly solved your problem? That was about the scaling patch. Disabling hardware scan while using 2.6.38 helped me. In the previous kernels the software scan is slow so don't bother trying. Funnily Mandriva has had no problems. So I would suggest trying it to see if you have the same problem I did. It seemed there were at least 2 bugs with this adapter but there might be more. Big thanks about disabling hardware scan tip. However in my case it seems to have opposite effect - OpenSUSE already sets disable_hw_scan=1 as default option for iwl3945. After changing it to 0, I finally have 6Mbit/s download on linux. Upload is still slower (~0.45Mbit/s vs 0.7Mbit/s on windows), but it is much smaller problem. That's odd. I use disable_hw_scan=1 because 0 causes great speed loss o.O Some users needs to enable hw scan for achieve good performance other needs to disable it for the same reason, eh bugger. Please re-open if still seem in current kernels |