linux-kernel - Re: [ath9k-devel] ath9k: massive unexplained latency in 2.6.27 (rc5, rc6, probably others)

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Date:	Mon, 22 Sep 2008 08:11:30 -0700
From:	"Steven Noonan" <steven@...inklabs.net>
To:	"Luis R. Rodriguez" <lrodriguez@...eros.com>
Cc:	"Luis Rodriguez" <Luis.Rodriguez@...eros.com>,
	linux-wireless <linux-wireless@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	"Senthilkumar Balasubramanian" 
	<Senthilkumar.Balasubramanian@...eros.com>,
	"ath9k-devel@...ts.ath9k.org" <ath9k-devel@...ts.ath9k.org>,
	"Johannes Berg" <johannes@...solutions.net>,
	"Ingo Molnar" <mingo@...e.hu>
Subject: Re: [ath9k-devel] ath9k: massive unexplained latency in 2.6.27 (rc5, rc6, probably others)

On Mon, Sep 22, 2008 at 1:06 AM, Luis R. Rodriguez
<lrodriguez@...eros.com> wrote:
> Please test the following patch.
>
> diff --git a/drivers/net/wireless/ath9k/core.c b/drivers/net/wireless/ath9k/core.c
> index c262ef2..9a51739 100644
> --- a/drivers/net/wireless/ath9k/core.c
> +++ b/drivers/net/wireless/ath9k/core.c
> @@ -681,10 +681,12 @@ int ath_open(struct ath_softc *sc, struct ath9k_channel *initial_chan)
>         * Enable MIB interrupts when there are hardware phy counters.
>         * Note we only do this (at the moment) for station mode.
>         */
> +#if 0
>        if (ath9k_hw_phycounters(ah) &&
>            ((sc->sc_ah->ah_opmode == ATH9K_M_STA) ||
>             (sc->sc_ah->ah_opmode == ATH9K_M_IBSS)))
>                sc->sc_imask |= ATH9K_INT_MIB;
> +#endif
>        /*
>         * Some hardware processes the TIM IE and fires an
>         * interrupt when the TIM bit is set.  For hardware
>

It didn't apply to -rc7, but I managed to apply it manually
(apparently you made this for wireless-testing?) and added the #if 0.
After 7 hours uptime with the driver, no apparent interrupt storm.

I'll do more thorough testing later, but I have a 3 hour drive today,
and some packing to do, so it'll need to wait a bit.

- Steven
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