From: Seth Forshee <seth.forshee@canonical.com>
To: Felix Fietkau <nbd@openwrt.org>
Cc: linux-wireless@vger.kernel.org,
"Luis R. Rodriguez" <mcgrof@qca.qualcomm.com>,
Jouni Malinen <jouni@qca.qualcomm.com>,
Vasanthakumar Thiagarajan <vthiagar@qca.qualcomm.com>,
Senthil Balasubramanian <senthilb@qca.qualcomm.com>
Subject: Re: CTS timeout issue with AR9285
Date: Thu, 2 Feb 2012 08:38:43 -0600 [thread overview]
Message-ID: <20120202143843.GB24483@ubuntu-macmini> (raw)
In-Reply-To: <4F2A830A.8000905@openwrt.org>
On Thu, Feb 02, 2012 at 01:35:22PM +0100, Felix Fietkau wrote:
> On 2012-02-02 5:25 AM, Seth Forshee wrote:
> > I recently updated a machine with AR9285 wireless from kernel version
> > 3.0 to 3.2 and saw that wireless had become slow and unreliable. It
> > seems that the problem is extremely frequent CTS timeouts, which began
> > happening with commit adb5066 (ath9k_hw: do not apply the 2.4 ghz ack
> > timeout workaround to cts). Restoring the CTS timeout to the value prior
> > to this commit on top of 3.2 gets performance back to what it was with
> > 3.0.
> >
> > I don't have any other ath9k cards lying around, but various other cards
> > are working fine with this router. Any ideas what's wrong here?
> Please try this patch:
>
> --- a/drivers/net/wireless/ath/ath9k/hw.c
> +++ b/drivers/net/wireless/ath/ath9k/hw.c
> @@ -1061,13 +1061,16 @@ void ath9k_hw_init_global_settings(struc
>
> /*
> * Workaround for early ACK timeouts, add an offset to match the
> - * initval's 64us ack timeout value.
> + * initval's 64us ack timeout value. Use 48us for the CTS timeout.
> * This was initially only meant to work around an issue with delayed
> * BA frames in some implementations, but it has been found to fix ACK
> * timeout issues in other cases as well.
> */
> - if (conf->channel && conf->channel->band == IEEE80211_BAND_2GHZ)
> + if (conf->channel && conf->channel->band == IEEE80211_BAND_2GHZ) {
> acktimeout += 64 - sifstime - ah->slottime;
> + ctstimeout += 48 - sifstime - ah->slottime;
> + }
> +
>
> ath9k_hw_set_sifs_time(ah, sifstime);
> ath9k_hw_setslottime(ah, slottime);
>
The wireless seems to be working fine with this patch.
next prev parent reply other threads:[~2012-02-02 14:38 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-02 4:25 CTS timeout issue with AR9285 Seth Forshee
2012-02-02 11:28 ` Mohammed Shafi
2012-02-02 14:20 ` Seth Forshee
2012-02-02 12:35 ` Felix Fietkau
2012-02-02 14:15 ` Martin Hundebøll
2012-02-02 14:22 ` Felix Fietkau
2012-02-02 14:38 ` Seth Forshee [this message]
2012-02-04 6:08 ` Marek Lindner
2012-02-04 10:24 ` Adrian Chadd
2012-02-04 20:18 ` Felix Fietkau
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