On Fri, May 27, 2011 at 1:16 PM, Adrian Chadd [off-list ref] wrote:

That should only really hit 0 if you're configuring a low TX power level.. ?

true.

Hm, I spy with my little eye a small bug with the eeprom power
handling for the v14 eeprom.
The modal header has:

       u8 pwrDecreaseFor2Chain;
       u8 pwrDecreaseFor3Chain;

but the EEPROM code is hard-coded to use -6 for 2-chain reduction and
-9 for 3-chain reduction.

yes, but I am not sure whether this configuration from eeprom is
needed for AR9003?
if they are hardcoding the data from eeprom may return 0 ?

hmmm in ath9k not exactly the same is there,
   REG_WRITE(ah, AR_PHY_POWER_TX_SUB,
                  ATH9K_POW_SM(pModal->pwrDecreaseFor3Chain, 6)
                  | ATH9K_POW_SM(pModal->pwrDecreaseFor2Chain, 0));

On 27 May 2011 15:18, Mohammed Shafi [off-list ref] wrote:

quoted

On Thu, May 26, 2011 at 10:13 PM, Daniel Halperin
[off-list ref] wrote:

quoted

This is the same fix as

   commit 841051602e3fa18ea468fe5a177aa92b6eb44b56
   Author: Matteo Croce [off-list ref]
   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.

Cc: stable@kernel.org
Signed-off-by: Daniel Halperin <redacted>
---
RFC: Blaise Gassend actually pointed these two bugs out on 12/7/2010 but no
one fixed. There was some discussion about refactoring/improving this code,
but it never seemed to get anywhere. See this thread:

   http://comments.gmane.org/gmane.linux.drivers.ath9k.devel/4601
---
 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(-)

diff --git a/drivers/net/wireless/ath/ath9k/ar9003_eeprom.c b/drivers/net/wireless/ath/ath9k/ar9003_eeprom.c
index 729534c..934e419 100644
--- a/drivers/net/wireless/ath/ath9k/ar9003_eeprom.c
+++ b/drivers/net/wireless/ath/ath9k/ar9003_eeprom.c

@@ -4645,10 +4645,16 @@ static void ar9003_hw_set_power_per_rate_table(struct ath_hw *ah,

       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;

should we make the scaledPower as '0' lets have the first check if it
fails, let us retain the  scaledPower obtained by
 scaledPower = min(powerLimit, maxRegAllowedPower);

am I missing something ?
making scaledPower affects this
  minCtlPower = (u8)min(twiceMaxEdgePower, scaledPower);

which in turn affects
 pPwrArray[i] =
                                         (u8)min((u16)pPwrArray[i],
                                                 minCtlPower);

which in turn affects target Power values

quoted

               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;
       }

diff --git a/drivers/net/wireless/ath/ath9k/eeprom_9287.c b/drivers/net/wireless/ath/ath9k/eeprom_9287.c
index 7856f0d..343fc9f 100644
--- a/drivers/net/wireless/ath/ath9k/eeprom_9287.c
+++ b/drivers/net/wireless/ath/ath9k/eeprom_9287.c

@@ -524,10 +524,16 @@ static void ath9k_hw_set_ar9287_power_per_rate_table(struct ath_hw *ah,

       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);
--
1.7.0.4


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shafi

-- 
shafi