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wireless: report reasonable bitrate for MCS rates through wext

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Previously, cfg80211 had reported "0" for MCS (i.e. 802.11n) bitrates
through the wireless extensions interface.  However, nl80211 was
converting MCS rates into a reasonable bitrate number.  This patch moves
the nl80211 code to cfg80211 where it is now shared between both the
nl80211 interface and the wireless extensions interface.

Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
John W. Linville
2009-12-09 16:43:52 -05:00
parent a252e749f1
commit 254416aae7
4 changed files with 38 additions and 39 deletions
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33
net/wireless/util.c
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@@ -720,3 +720,36 @@ int cfg80211_change_iface(struct cfg80211_registered_device *rdev,
return err;
}
u16 cfg80211_calculate_bitrate(struct rate_info *rate)
{
int modulation, streams, bitrate;
if (!(rate->flags & RATE_INFO_FLAGS_MCS))
return rate->legacy;
/* the formula below does only work for MCS values smaller than 32 */
if (rate->mcs >= 32)
return 0;
modulation = rate->mcs & 7;
streams = (rate->mcs >> 3) + 1;
bitrate = (rate->flags & RATE_INFO_FLAGS_40_MHZ_WIDTH) ?
13500000 : 6500000;
if (modulation < 4)
bitrate *= (modulation + 1);
else if (modulation == 4)
bitrate *= (modulation + 2);
else
bitrate *= (modulation + 3);
bitrate *= streams;
if (rate->flags & RATE_INFO_FLAGS_SHORT_GI)
bitrate = (bitrate / 9) * 10;
/* do NOT round down here */
return (bitrate + 50000) / 100000;
}