Red Hat Bugzilla – Bug 498719
[patch] mac80211: nullfunc and hidden SSID fixes
Last modified: 2009-09-02 04:59:37 EDT
Created attachment 342178 [details]
scanning fixes for mac80211
When returning from a scan, the stack tried to probe the last-scanned SSID, which is completely wrong, and may not even have existed. It's supposed to be probing the previously associated SSID instead. This caused the stack to periodically disconnect from hidden-SSID access points becuase the hidden SSID doesn't show up in the scan list, and the probe-request to that SSID is required to determine if its still present.
The mac80211 stack sends null packets when beginning a scan to alert the AP that it should buffer frames for the STA while the STA is scanning. However, the TX path of mac80211 would simply drop these frames on the floor, causing the AP not to buffer frames, and leading to deauthentications due to excessive retries on the AP.
This leads to choppy or broken streaming video, intermittent connection failures when using NetworkManager due to the extra steps required to reauthenticate to the AP when it has dropped you due to excessive retries, etc.
This patch came out of the debugging sessions I've been having with a large customer of the past 3 weeks. See bug #493745 & IT #283289 for the details.
Test kernels w/ the attached patch are available here:
Please give them a try and post the results...thanks!
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release. Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products. This request is not yet committed for inclusion in an Update
Dan - Thanks for your support on these patches. Huge improvement in wireless stability.
I'll post in the IssueTracker ticket to advocate for inclusion in RHEL 5.4
You can download this test kernel from http://people.redhat.com/dzickus/el5
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