svn commit: r210110 - head/sys/dev/iwn

[Bernhard Schmidt]

Author: bschmidt
Date: Thu Jul 15 09:34:00 2010
New Revision: 210110
URL: http://svn.freebsd.org/changeset/base/210110

Log:
  Detect active chains differently to work around a firmware bug which
  would mark non-existing chains as active.
  
  Obtained from:	OpenBSD
  MFC after:	1 week

Modified:
  head/sys/dev/iwn/if_iwn.c

Modified: head/sys/dev/iwn/if_iwn.c
==============================================================================
--- head/sys/dev/iwn/if_iwn.c	Thu Jul 15 09:30:54 2010	(r210109)
+++ head/sys/dev/iwn/if_iwn.c	Thu Jul 15 09:34:00 2010	(r210110)
@@ -4134,10 +4134,14 @@ iwn_collect_noise(struct iwn_softc *sc,
 	val = MAX(calib->rssi[2], val);
 
 	/* Determine which antennas are connected. */
-	sc->chainmask = 0;
+	sc->chainmask = sc->rxchainmask;
 	for (i = 0; i < 3; i++)
-		if (val - calib->rssi[i] <= 15 * 20)
-			sc->chainmask |= 1 << i;
+		if (val - calib->rssi[i] > 15 * 20)
+			sc->chainmask &= ~(1 << i);
+	DPRINTF(sc, IWN_DEBUG_CALIBRATE,
+	    "%s: RX chains mask: theoretical=0x%x, actual=0x%x\n",
+	    __func__, sc->rxchainmask, sc->chainmask);
+
 	/* If none of the TX antennas are connected, keep at least one. */
 	if ((sc->chainmask & sc->txchainmask) == 0)
 		sc->chainmask |= IWN_LSB(sc->txchainmask);