[RFC] cfg80211: allow HT20 channels on devices incabable of HT40

[Helmut Schaa <helmut.schaa@googlemail.com>]

I was just trying to set up a rt2800 AP but hostapd was unable to
set the channel when configuring 11n.

rt2800 doesn't support HT40 yet, that's why it doesn't set
IEEE80211_HT_CAP_SUP_WIDTH_20_40 and cfg80211 refuses to set the
channel when the device doesn't support IEEE80211_HT_CAP_SUP_WIDTH_20_40
even if  a HT20 only channel should be set.

Did I miss anything or should it be allowed to set a HT20 channel
on a HT capable device that doesn't allow HT40?

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
---
 net/wireless/chan.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index d92d088..647832a 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -35,8 +35,9 @@ rdev_freq_to_chan(struct cfg80211_registered_device *rdev,
 		if (!ht_cap->ht_supported)
 			return NULL;
 
-		if (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
-		    ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT)
+		if (channel_type != NL80211_CHAN_HT20 &&
+		    (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
+		    ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT))
 			return NULL;
 	}
 
-- 
1.6.4.2