2014-02-27 13:36:23

by Sylvain Roger Rieunier

[permalink] [raw]
Subject: [PATCH] ath9k: fix invalid max frame length

From: Sylvain Roger Rieunier <[email protected]>

According to 802.11n-2012 standard in paragraph PPDU Fromat(20.3.2) HT-mixed
format Hearder PPDU contains : L_STF, L_LTF, L_SIG, HT_SIG, HT_STF, HT_LTF
they are symbols in the preamble, there are in time unit(us) that's for why
it can't be computed in bytes

Signed-off-by: Sylvain ROGER RIEUNIER <[email protected]>
---
drivers/net/wireless/ath/ath9k/xmit.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index 312314c..544186e 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -1040,11 +1040,11 @@ static int ath_max_framelen(int usec, int mcs, bool ht40, bool sgi)
int symbols, bits;
int bytes = 0;

+ usec -= L_STF + L_LTF + L_SIG + HT_SIG + HT_STF + HT_LTF(streams);
symbols = sgi ? TIME_SYMBOLS_HALFGI(usec) : TIME_SYMBOLS(usec);
bits = symbols * bits_per_symbol[mcs % 8][ht40] * streams;
bits -= OFDM_PLCP_BITS;
bytes = bits / 8;
- bytes -= L_STF + L_LTF + L_SIG + HT_SIG + HT_STF + HT_LTF(streams);
if (bytes > 65532)
bytes = 65532;

--
1.7.10.4