* ath9k: reports wrong GI/bandwidth (bug)
@ 2011-12-09 10:36 Johannes Berg
2011-12-09 19:42 ` Adrian Chadd
0 siblings, 1 reply; 4+ messages in thread
From: Johannes Berg @ 2011-12-09 10:36 UTC (permalink / raw)
To: linux-wireless; +Cc: Luis R. Rodriguez
[-- Attachment #1: Type: text/plain, Size: 877 bytes --]
I'm testing some things between my ath9k AP (tp link wr1043nd) and Intel
6205 passing traffic, and an AR9300 capturing it.
I'm seeing ath9k (the capture card) report different GI/bandwidth for
packets within a single AMPDU, see the attached pcap file. I know they
were all in a single AMPDU because the receive side (Intel card)
reported it that way, and it also reported MCS 15 (no short GI) for all
of the frames.
In the attached pcap file, you can see it report MCS 15 for all frames
(except the BA obviously), but with three (out of four possible)
combinations of short GI/BW, it reports some frames with 40 MHz and some
with 40 MHz/short GI -- the only valid combination is neither of those.
In other packets I've also seen it report just short GI, so I've seen
all four combinations (but only three in the attached file).
Seems it's completely confused! :-)
johannes
[-- Attachment #2: ampdu-confusion.pcap --]
[-- Type: application/x-extension-pcap, Size: 28880 bytes --]
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: ath9k: reports wrong GI/bandwidth (bug)
2011-12-09 10:36 ath9k: reports wrong GI/bandwidth (bug) Johannes Berg
@ 2011-12-09 19:42 ` Adrian Chadd
2011-12-09 20:31 ` Johannes Berg
0 siblings, 1 reply; 4+ messages in thread
From: Adrian Chadd @ 2011-12-09 19:42 UTC (permalink / raw)
To: Johannes Berg; +Cc: linux-wireless, Luis R. Rodriguez
Can you see whether the -final- frame in an A-MPDU has the correct GI bit set?
adrian
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: ath9k: reports wrong GI/bandwidth (bug)
2011-12-09 19:42 ` Adrian Chadd
@ 2011-12-09 20:31 ` Johannes Berg
2011-12-11 0:02 ` Adrian Chadd
0 siblings, 1 reply; 4+ messages in thread
From: Johannes Berg @ 2011-12-09 20:31 UTC (permalink / raw)
To: Adrian Chadd; +Cc: linux-wireless, Luis R. Rodriguez
On Sat, 2011-12-10 at 06:42 +1100, Adrian Chadd wrote:
> Can you see whether the -final- frame in an A-MPDU has the correct GI bit set?
In a dozen or so cases in the original capture file, it does seem to be
correct in those cases. Not that it helps much, we could've missed the
last one :-)
johannes
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: ath9k: reports wrong GI/bandwidth (bug)
2011-12-09 20:31 ` Johannes Berg
@ 2011-12-11 0:02 ` Adrian Chadd
0 siblings, 0 replies; 4+ messages in thread
From: Adrian Chadd @ 2011-12-11 0:02 UTC (permalink / raw)
To: Johannes Berg; +Cc: linux-wireless, Luis R. Rodriguez
On 10 December 2011 07:31, Johannes Berg <johannes@sipsolutions.net> wrote:
> On Sat, 2011-12-10 at 06:42 +1100, Adrian Chadd wrote:
>> Can you see whether the -final- frame in an A-MPDU has the correct GI bit set?
>
> In a dozen or so cases in the original capture file, it does seem to be
> correct in those cases. Not that it helps much, we could've missed the
> last one :-)
Ok. Well, this just adds to the "only the last frame has all the
"correct" RX state" thing :)
Adrian
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2011-12-11 0:02 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2011-12-09 10:36 ath9k: reports wrong GI/bandwidth (bug) Johannes Berg
2011-12-09 19:42 ` Adrian Chadd
2011-12-09 20:31 ` Johannes Berg
2011-12-11 0:02 ` Adrian Chadd
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