mac80211: handle power constraint/country IE better
Currently, mac80211 uses the power constraint IE, and reduces
the regulatory max TX power by it. This can cause issues if
the AP is advertising a large power constraint value matching
a high TX power in its country IE, for example in this case:
...
Country: US Environment: Indoor/Outdoor
...
Channels [157 - 157] @ 30 dBm
...
Power constraint: 13 dB
...
What happened here is that our local regulatory TX power is
15 dBm, and gets reduced by 13 dB so we end up with only
2 dBm effective TX power, which is way too low.
Instead, handle the country IE/power constraint IE combined
and restrict our TX power to the max of the regulatory power
and the maximum power advertised by the AP, in this case
17 dBm (= 30 dBm - 13 dB).
Also print a message when this happens to let the user know
and help us debug issues with it.
Reported-by: Carl A. Cook <CACook@quantum-equities.com>
Tested-by: Carl A. Cook <CACook@quantum-equities.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index d11a6f8..8c80455 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1059,7 +1059,7 @@
bool disable_dynamic_ps;
int user_power_level; /* in dBm */
- int power_constr_level; /* in dBm */
+ int ap_power_level; /* in dBm */
enum ieee80211_smps_mode smps_mode;