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zd1211rw: firmware needs duration_id set to zero for non-pspoll frames

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Some devices (iwl5100) cannot connect to zd1211rw based AP. It appears that
zd1211 firmware messes up duration_id field if it is not set to zero by driver.

Sniffing traffic shows that zd1211 is transmitting frames with duration_id bits
14 and 15 set and other bits appearing random. Setting duration_id at driver to
zero results zd1211 outputting sane duration_id. This means that firmware is
setting correct values itself and expects duration_id to be zero in first
place.

Looking at vendor driver shows that only PSPoll frames have duration_id set by
driver, for other frames duration_id left zero.

Original bug-report and attached patch at:
  http://sourceforge.net/mailarchive/message.php?msg_id=28759111

Reported-by: Tomas Vanek <Tomas.Vanek@fbl.cz>
[modified original patch from bug-report, added check for pspoll frame]
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Tomas Vanek 2012-02-05 15:51:53 +02:00 committed by John W. Linville
parent 2e6b411971
commit e81a7bd555
1 changed files with 8 additions and 0 deletions
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8
drivers/net/wireless/zd1211rw/zd_mac.c
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@ -866,6 +866,14 @@ static int fill_ctrlset(struct zd_mac *mac,
ZD_ASSERT(frag_len <= 0xffff);
/*
* Firmware computes the duration itself (for all frames except PSPoll)
* and needs the field set to 0 at input, otherwise firmware messes up
* duration_id and sets bits 14 and 15 on.
*/
if (!ieee80211_is_pspoll(hdr->frame_control))
hdr->duration_id = 0;
txrate = ieee80211_get_tx_rate(mac->hw, info);
cs->modulation = txrate->hw_value;