[PATCH] b43: don't fall back to CCK rates on 5GHz OFDM for RTS frames

[PATCH] b43: don't fall back to CCK rates on 5GHz OFDM for RTS frames

[Adrian Chadd]

This fixes a small issue with selecting fallback rates for
RTS frames.  For OFDM PHY rates in 5GHz mode we shouldn't
fall back to CCK.

Adrian Chadd (1):
  [b43] don't unconditionally fall back to CCK if the rate is 6MB OFDM.

 drivers/net/wireless/broadcom/b43/xmit.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

-- 
2.6.3

[PATCH] [b43] don't unconditionally fall back to CCK if the rate is 6MB OFDM.

[Adrian Chadd]

Check the current PHY operating mode (gmode) to see if we should
fall back from 6MB OFDM to 11MB CCK.  For 5GHz operation this isn't
allowed.

Note, the fallback lookup is only done for RTS rates; normal fallback
rates are done via mac80211 and aren't affected by this change.

	Signed-off-by: Adrian Chadd <adrian@freebsd.org>
---
 drivers/net/wireless/broadcom/b43/xmit.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/broadcom/b43/xmit.c b/drivers/net/wireless/broadcom/b43/xmit.c
index f620126..7edbcdb 100644
--- a/drivers/net/wireless/broadcom/b43/xmit.c
+++ b/drivers/net/wireless/broadcom/b43/xmit.c
@@ -205,7 +205,7 @@ static u16 b43_generate_tx_phy_ctl1(struct b43_wldev *dev, u8 bitrate)
 	return control;
 }
 
-static u8 b43_calc_fallback_rate(u8 bitrate)
+static u8 b43_calc_fallback_rate(u8 bitrate, int gmode)
 {
 	switch (bitrate) {
 	case B43_CCK_RATE_1MB:
@@ -216,8 +216,15 @@ static u8 b43_calc_fallback_rate(u8 bitrate)
 		return B43_CCK_RATE_2MB;
 	case B43_CCK_RATE_11MB:
 		return B43_CCK_RATE_5MB;
+	/*
+	 * Don't just fallback to CCK; it may be in 5GHz operation
+	 * and falling back to CCK won't work out very well.
+	 */
 	case B43_OFDM_RATE_6MB:
-		return B43_CCK_RATE_5MB;
+		if (gmode)
+			return B43_CCK_RATE_5MB;
+		else
+			return B43_OFDM_RATE_6MB;
 	case B43_OFDM_RATE_9MB:
 		return B43_OFDM_RATE_6MB;
 	case B43_OFDM_RATE_12MB:
@@ -438,7 +445,7 @@ int b43_generate_txhdr(struct b43_wldev *dev,
 
 		rts_rate = rts_cts_rate ? rts_cts_rate->hw_value : B43_CCK_RATE_1MB;
 		rts_rate_ofdm = b43_is_ofdm_rate(rts_rate);
-		rts_rate_fb = b43_calc_fallback_rate(rts_rate);
+		rts_rate_fb = b43_calc_fallback_rate(rts_rate, phy->gmode);
 		rts_rate_fb_ofdm = b43_is_ofdm_rate(rts_rate_fb);
 
 		if (rates[0].flags & IEEE80211_TX_RC_USE_CTS_PROTECT) {
-- 
2.6.3

Re: [PATCH] [b43] don't unconditionally fall back to CCK if the rate is 6MB OFDM.

[Kalle Valo]

Adrian Chadd <adrian@freebsd.org> writes:

> Check the current PHY operating mode (gmode) to see if we should
> fall back from 6MB OFDM to 11MB CCK.  For 5GHz operation this isn't
> allowed.
>
> Note, the fallback lookup is only done for RTS rates; normal fallback
> rates are done via mac80211 and aren't affected by this change.
>
> 	Signed-off-by: Adrian Chadd <adrian@freebsd.org>

Two cosmetic problems: s/\[b43\]/b43: / and remove the tab before the
S-o-b. I can fix them before applying. But most probably I'll apply this
only after the merge window closes, in two weeks or so.

-- 
Kalle Valo

Re: b43: don't unconditionally fall back to CCK if the rate is 6MB OFDM.

[Kalle Valo]

Adrian Chadd <adrian@freebsd.org> wrote:
> Check the current PHY operating mode (gmode) to see if we should
> fall back from 6MB OFDM to 11MB CCK.  For 5GHz operation this isn't
> allowed.
> 
> Note, the fallback lookup is only done for RTS rates; normal fallback
> rates are done via mac80211 and aren't affected by this change.
> 
> Signed-off-by: Adrian Chadd <adrian@freebsd.org>

Thanks, 1 patch applied to wireless-drivers-next.git:

d0b03439f784 b43: don't unconditionally fall back to CCK if the rate is 6MB OFDM.

-- 
Sent by pwcli
https://patchwork.kernel.org/patch/9108351/