[3.5.y.z extended stable] Patch "rt2800: fix wrong TX power compensation" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    rt2800: fix wrong TX power compensation

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From b38ce0c24dc77824b8e9e9a83dfdce2d434e45c7 Mon Sep 17 00:00:00 2001
From: Stanislaw Gruszka <sgruszka at redhat.com>
Date: Mon, 26 Aug 2013 15:18:53 +0200
Subject: [PATCH] rt2800: fix wrong TX power compensation

commit 6e956da2027c767859128b9bfef085cf2a8e233b upstream.

We should not do temperature compensation on devices without
EXTERNAL_TX_ALC bit set (called DynamicTxAgcControl on vendor driver).
Such devices can have totally bogus TSSI parameters on the EEPROM,
but still threaded by us as valid and result doing wrong TX power
calculations.

This fix inability to connect to AP on slightly longer distance on
some Ralink chips/devices.

Reported-and-tested-by: Fabien ADAM <id2ndr at crocobox.org>
Signed-off-by: Stanislaw Gruszka <sgruszka at redhat.com>
Signed-off-by: John W. Linville <linville at tuxdriver.com>
[ luis: backported to 3.5:
  - use rt2x00_eeprom_read() instead of rt2800_eeprom_read() ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/wireless/rt2x00/rt2800lib.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/wireless/rt2x00/rt2800lib.c b/drivers/net/wireless/rt2x00/rt2800lib.c
index 1c60904..b81f2b6 100644
--- a/drivers/net/wireless/rt2x00/rt2800lib.c
+++ b/drivers/net/wireless/rt2x00/rt2800lib.c
@@ -2181,6 +2181,13 @@ static int rt2800_get_gain_calibration_delta(struct rt2x00_dev *rt2x00dev)
 	int i;

 	/*
+	 * First check if temperature compensation is supported.
+	 */
+	rt2x00_eeprom_read(rt2x00dev, EEPROM_NIC_CONF1, &eeprom);
+	if (!rt2x00_get_field16(eeprom, EEPROM_NIC_CONF1_EXTERNAL_TX_ALC))
+		return 0;
+
+	/*
 	 * Read TSSI boundaries for temperature compensation from
 	 * the EEPROM.
 	 *
--
1.8.3.2