Date: Mon, 3 Jun 2013 19:07:12 GMT From: adrian chadd <adrian@FreeBSD.org> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/179269: [ath] [AR9285] RX antenna diversity is not functioning correctly; breaks single-antenna designs Message-ID: <201306031907.r53J7CkP001401@oldred.freebsd.org> Resent-Message-ID: <201306031910.r53JA0Vu014290@freefall.freebsd.org>
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>Number: 179269
>Category: kern
>Synopsis: [ath] [AR9285] RX antenna diversity is not functioning correctly; breaks single-antenna designs
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Mon Jun 03 19:10:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator: adrian chadd
>Release: FreeBSD-10
>Organization:
>Environment:
>Description:
This is applicable to -9 and -8 as well.
The AR9285 is a 1x1 design with a twist on "classic" style antenna diversity. The MAC can choose:
* RX on antenna 1 or 2;
* RX on both, by using a "mixer configuration" to mix the signals from both antennas a specific way;
* RX on both, by selecting either antenna 1 or 2 (ie, classic diversity) based on signal level;
* RX on both, by using the above mixer configuration (well two - main and alternate) and selecting one based on signal level
Now, by default, we're only doing RX on a single antenna. The AR_DEF_ANTENNA register controls the static antenna selection if fast diversity isn't enabled.
However! The AR5416 HAL does this:
/*
* Preserve the antenna on a channel change
*/
saveDefAntenna = OS_REG_READ(ah, AR_DEF_ANTENNA);
if (saveDefAntenna == 0) /* XXX magic constants */
saveDefAntenna = 1;
. which means RX will only occur on antenna #2 if antenna diversity is disabled.
So in one antenna solutions (antenna #1 / Main is connected) the unit will TX through the antenna, but RX through the unconnected port.
>How-To-Repeat:
* AR9285
* Connect an antenna to antenna #1
* do NOT connect an antenna to antenna #2
* Try being a station for a while
>Fix:
This workaround (for the AR5416, I guess) needs to be made conditional.
Fast and slow antenna diversity should be enabled as well. I'll go through the code and figure out why that isn't enabled.
>Release-Note:
>Audit-Trail:
>Unformatted:
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