[PATCH] ath5k: ignore the return value of ath5k_hw_noise_floor_calibration

[PATCH] ath5k: ignore the return value of ath5k_hw_noise_floor_calibration

[Felix Fietkau]

Noise floor calibration occasionally fails on Atheros hardware.
This is not fatal and can happen if there's simply too much 
noise on the air. Ignoring the calibration error is the right
thing to do here, because when the error is ignored, the hardware
will still work, whereas if the error causes the driver to bail out
of a bigger configuration function and does not configure the tx
queues or the IMR (as is the case in reset.c), the hw no longer
works properly until the next reset.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

diff --git a/drivers/net/wireless/ath5k/phy.c b/drivers/net/wireless/ath5k/phy.c
--- a/drivers/net/wireless/ath5k/phy.c
+++ b/drivers/net/wireless/ath5k/phy.c
@@ -2196,9 +2196,7 @@ static int ath5k_hw_rf5110_calibrate(struct ath5k_hw *ah,
 		return ret;
 	}
 
-	ret = ath5k_hw_noise_floor_calibration(ah, channel->center_freq);
-	if (ret)
-		return ret;
+	ath5k_hw_noise_floor_calibration(ah, channel->center_freq);
 
 	/*
 	 * Re-enable RX/TX and beacons
diff --git a/drivers/net/wireless/ath5k/reset.c b/drivers/net/wireless/ath5k/reset.c
--- a/drivers/net/wireless/ath5k/reset.c
+++ b/drivers/net/wireless/ath5k/reset.c
@@ -842,9 +842,7 @@ int ath5k_hw_reset(struct ath5k_hw *ah, enum nl80211_iftype op_mode,
 	 *
 	 * XXX: Find an interval that's OK for all cards...
 	 */
-	ret = ath5k_hw_noise_floor_calibration(ah, channel->center_freq);
-	if (ret)
-		return ret;
+	ath5k_hw_noise_floor_calibration(ah, channel->center_freq);
 
 	/*
 	 * Reset queues and start beacon timers at the end of the reset routine

Re: [PATCH] ath5k: ignore the return value of ath5k_hw_noise_floor_calibration

[Tim Gardner]

Felix Fietkau wrote:
> Noise floor calibration occasionally fails on Atheros hardware.
> This is not fatal and can happen if there's simply too much 
> noise on the air. Ignoring the calibration error is the right
> thing to do here, because when the error is ignored, the hardware
> will still work, whereas if the error causes the driver to bail out
> of a bigger configuration function and does not configure the tx
> queues or the IMR (as is the case in reset.c), the hw no longer
> works properly until the next reset.
> 
> Signed-off-by: Felix Fietkau <nbd@openwrt.org>
> 
> diff --git a/drivers/net/wireless/ath5k/phy.c b/drivers/net/wireless/ath5k/phy.c
> --- a/drivers/net/wireless/ath5k/phy.c
> +++ b/drivers/net/wireless/ath5k/phy.c
> @@ -2196,9 +2196,7 @@ static int ath5k_hw_rf5110_calibrate(struct ath5k_hw *ah,
>  		return ret;
>  	}
>  
> -	ret = ath5k_hw_noise_floor_calibration(ah, channel->center_freq);
> -	if (ret)
> -		return ret;
> +	ath5k_hw_noise_floor_calibration(ah, channel->center_freq);
>  
>  	/*
>  	 * Re-enable RX/TX and beacons
> diff --git a/drivers/net/wireless/ath5k/reset.c b/drivers/net/wireless/ath5k/reset.c
> --- a/drivers/net/wireless/ath5k/reset.c
> +++ b/drivers/net/wireless/ath5k/reset.c
> @@ -842,9 +842,7 @@ int ath5k_hw_reset(struct ath5k_hw *ah, enum nl80211_iftype op_mode,
>  	 *
>  	 * XXX: Find an interval that's OK for all cards...
>  	 */
> -	ret = ath5k_hw_noise_floor_calibration(ah, channel->center_freq);
> -	if (ret)
> -		return ret;
> +	ath5k_hw_noise_floor_calibration(ah, channel->center_freq);
>  
>  	/*
>  	 * Reset queues and start beacon timers at the end of the reset routine
> --
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> 

ACK

While I'm not sure I agree with your theory on why noise floor
calibration fails, this patch certainly cuts down on log noise without
introducing any adverse side effects.

rtg
-- 
Tim Gardner timg@tpi.com www.tpi.com
OR 503-601-0234 x102 MT 406-443-5357

[PATCH] ath5k: ignore the return value of ath5k_hw_noise_floor_calibration

[darklight]

hi,

some weeks ago Felix Fietkau posted a patch for the "ath5k phy0:
unsupported jumbo" warnings (see here:
http://article.gmane.org/gmane.linux.kernel.wireless.general/23430 )
I just had the same problem - after applying Felix' patch the warnings
went down from 50-100 per day to 5.

as a quick note: I did not just apply this patch, instead I replaced
Linus' upstream wireless stack with the one from wireless-testing
(using kernel version 2.6.28)

I hope Felix' patch can get into Linus' kernel (mainline) so other
users can profit from this

oh and just to make sure this patch will get accepted:
ath5k_hw_noise_floor_calibration was called without verifying it's
result in ath5k_hw_rf511x_calibrate -> so in theory this patch is
clean an get into mainline (just to be fair: I must admit I'm not
familiar with the mac80211 nor with ath5k code)

regards,
Martin

Re: [PATCH] ath5k: ignore the return value of ath5k_hw_noise_floor_calibration

[Bob Copeland]

On Fri, Jan 9, 2009 at 8:21 PM, darklight
<darklight.xdarklight@googlemail.com> wrote:
> hi,
>
> some weeks ago Felix Fietkau posted a patch for the "ath5k phy0:
> unsupported jumbo" warnings (see here:
> http://article.gmane.org/gmane.linux.kernel.wireless.general/23430 )
> I just had the same problem - after applying Felix' patch the warnings
> went down from 50-100 per day to 5.

It's already in Linus' tree for 2.6.29 (CCed stable@kernel.org).

Greg / stable, can you take 8b0162a3dc5c30e862b7a73da29e32de3170f5e4 for
2.6.28.X?

(It's not unsupported jumbo warnings, it's for noise floor calibration
failures, as in the subject of this email.)

-- 
Bob Copeland %% www.bobcopeland.com

Re: [PATCH] ath5k: ignore the return value of ath5k_hw_noise_floor_calibration

[John W. Linville]

On Sat, Jan 10, 2009 at 02:21:44AM +0100, darklight wrote:
> hi,
> 
> some weeks ago Felix Fietkau posted a patch for the "ath5k phy0:
> unsupported jumbo" warnings (see here:
> http://article.gmane.org/gmane.linux.kernel.wireless.general/23430 )
> I just had the same problem - after applying Felix' patch the warnings
> went down from 50-100 per day to 5.
> 
> as a quick note: I did not just apply this patch, instead I replaced
> Linus' upstream wireless stack with the one from wireless-testing
> (using kernel version 2.6.28)
> 
> I hope Felix' patch can get into Linus' kernel (mainline) so other
> users can profit from this

It is in Linus' kernel right now:

commit 8b0162a3dc5c30e862b7a73da29e32de3170f5e4
Author: Felix Fietkau <nbd@openwrt.org>
Date:   Mon Nov 3 11:27:38 2008 +0100

    ath5k: ignore the return value of ath5k_hw_noise_floor_calibration

    Noise floor calibration occasionally fails on Atheros hardware.
    This is not fatal and can happen if there's simply too much
    noise on the air. Ignoring the calibration error is the right
    thing to do here, because when the error is ignored, the hardware
    will still work, whereas if the error causes the driver to bail out
    of a bigger configuration function and does not configure the tx
    queues or the IMR (as is the case in reset.c), the hw no longer
    works properly until the next reset.

    Signed-off-by: Felix Fietkau <nbd@openwrt.org>
    Signed-off-by: John W. Linville <linville@tuxdriver.com>

Hth!

John
-- 
John W. Linville		Someday the world will need a hero, and you
linville@tuxdriver.com			might be all we have.  Be ready.