[19/89] ath9k: fix two more bugs in tx power

[Greg KH]

2.6.39-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Daniel Halperin <dhalperi@xxxxxxxxxxxxxxxxx>

commit 21fdc87248d1d28492c775e05fa92b3c8c7bc8db upstream.

This is the same fix as

   commit 841051602e3fa18ea468fe5a177aa92b6eb44b56
   Author: Matteo Croce <technoboy85@xxxxxxxxx>
   Date:   Fri Dec 3 02:25:08 2010 +0100

   The ath9k driver subtracts 3 dBm to the txpower as with two radios the
   signal power is doubled.
   The resulting value is assigned in an u16 which overflows and makes
   the card work at full power.

in two more places. I grepped the ath tree and didn't find any others.

Signed-off-by: Daniel Halperin <dhalperi@xxxxxxxxxxxxxxxxx>
Signed-off-by: John W. Linville <linville@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/net/wireless/ath/ath9k/ar9003_eeprom.c |   10 ++++++++--
 drivers/net/wireless/ath/ath9k/eeprom_9287.c   |   10 ++++++++--
 2 files changed, 16 insertions(+), 4 deletions(-)

--- a/drivers/net/wireless/ath/ath9k/ar9003_eeprom.c
+++ b/drivers/net/wireless/ath/ath9k/ar9003_eeprom.c
@@ -4598,10 +4598,16 @@ static void ar9003_hw_set_power_per_rate
 	case 1:
 		break;
 	case 2:
-		scaledPower -= REDUCE_SCALED_POWER_BY_TWO_CHAIN;
+		if (scaledPower > REDUCE_SCALED_POWER_BY_TWO_CHAIN)
+			scaledPower -= REDUCE_SCALED_POWER_BY_TWO_CHAIN;
+		else
+			scaledPower = 0;
 		break;
 	case 3:
-		scaledPower -= REDUCE_SCALED_POWER_BY_THREE_CHAIN;
+		if (scaledPower > REDUCE_SCALED_POWER_BY_THREE_CHAIN)
+			scaledPower -= REDUCE_SCALED_POWER_BY_THREE_CHAIN;
+		else
+			scaledPower = 0;
 		break;
 	}
 
--- a/drivers/net/wireless/ath/ath9k/eeprom_9287.c
+++ b/drivers/net/wireless/ath/ath9k/eeprom_9287.c
@@ -522,10 +522,16 @@ static void ath9k_hw_set_ar9287_power_pe
 	case 1:
 		break;
 	case 2:
-		scaledPower -= REDUCE_SCALED_POWER_BY_TWO_CHAIN;
+		if (scaledPower > REDUCE_SCALED_POWER_BY_TWO_CHAIN)
+			scaledPower -= REDUCE_SCALED_POWER_BY_TWO_CHAIN;
+		else
+			scaledPower = 0;
 		break;
 	case 3:
-		scaledPower -= REDUCE_SCALED_POWER_BY_THREE_CHAIN;
+		if (scaledPower > REDUCE_SCALED_POWER_BY_THREE_CHAIN)
+			scaledPower -= REDUCE_SCALED_POWER_BY_THREE_CHAIN;
+		else
+			scaledPower = 0;
 		break;
 	}
 	scaledPower = max((u16)0, scaledPower);


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