I've done a bit more investigating. Hopefully some of this will be useful. I started a large file copy (~350MB) to another computer on the LAN (via SMB). On other OSes (Oneiric, Windows), the transfer occurs at a steady 2 Mbps or thereabouts. On precise the transfer rate will hit that level occasionally but frequently fluctuates lower and sometimes stops completely for several seconds at a time. Every now and then it will stop for so long that the transfer times out and fails.
--- I took a Wireshark capture of the transfer, and managed to snip out a decently small section that included both a successful block, a failed block, and a complete 2-second pause. Frames 1 - 72: A successful block. Not necessarily quite at full speed because of TCP window sizing, but that's what *all* the blocks look like on Oneiric and Windows. Frames 73 - 129: A bad block. The far end sends acks for packets we don't appear to have sent, however we must have sent them because they are necessary to reconstruct the "Write AndX Request" which the far end then replies to. Frames 130 - 241: A few more bad blocks similar to the previous one. Frames 242 - 266: The connection stutters for a few seconds, which was visible in the file transfer progress bar. I have no idea what's going on here protocol-wise, but something's not right. The remainder of the file is a partial block that didn't get fully captured. --- The far end has behaved sanely in every other test I've run, and this wireless card has behaved sanely in all tests I've run on other OSes. Based on the bad block in frames 73-129, it looks like some packets are getting successfully put on the air, but not registered as sent properly with the stack. When the far end acks or replies to those packets, the local machine gets confused. Hopefully some of this is helpful in tracking down the bug. ** Attachment added: "Wireshark capture of traffic during hiccup" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/902420/+attachment/2661860/+files/example.pcap -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/902420 Title: AR922X Wireless flaky since upgrade to Precise To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/902420/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
