svn commit: r330202 - stable/11/sys/dev/iwm

[Eitan Adler]

Author: eadler
Date: Thu Mar  1 06:34:48 2018
New Revision: 330202
URL: https://svnweb.freebsd.org/changeset/base/330202

Log:
  MFC r318012:
  
  [iwm] Allow listening on both chains/atennas to get diversity.
  
  This might improve throughput slightly when far from the accesspoint,
  apparently by allowing the firmware to listen on either of the two
  antennas (if there are two, i.e. on 7260/7265/8260), whichever has
  a better reception.

Modified:
  stable/11/sys/dev/iwm/if_iwm_phy_ctxt.c
  stable/11/sys/dev/iwm/if_iwm_util.c
  stable/11/sys/dev/iwm/if_iwm_util.h
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/sys/dev/iwm/if_iwm_phy_ctxt.c
==============================================================================
--- stable/11/sys/dev/iwm/if_iwm_phy_ctxt.c	Thu Mar  1 06:34:21 2018	(r330201)
+++ stable/11/sys/dev/iwm/if_iwm_phy_ctxt.c	Thu Mar  1 06:34:48 2018	(r330202)
@@ -217,6 +217,18 @@ iwm_mvm_phy_ctxt_cmd_data(struct iwm_softc *sc,
 	idle_cnt = chains_static;
 	active_cnt = chains_dynamic;
 
+	/* In scenarios where we only ever use a single-stream rates,
+	 * i.e. legacy 11b/g/a associations, single-stream APs or even
+	 * static SMPS, enable both chains to get diversity, improving
+	 * the case where we're far enough from the AP that attenuation
+	 * between the two antennas is sufficiently different to impact
+	 * performance.
+	 */
+	if (active_cnt == 1 && iwm_mvm_rx_diversity_allowed(sc)) {
+		idle_cnt = 2;
+		active_cnt = 2;
+	}
+
 	cmd->rxchain_info = htole32(iwm_mvm_get_valid_rx_ant(sc) <<
 					IWM_PHY_RX_CHAIN_VALID_POS);
 	cmd->rxchain_info |= htole32(idle_cnt << IWM_PHY_RX_CHAIN_CNT_POS);

Modified: stable/11/sys/dev/iwm/if_iwm_util.c
==============================================================================
--- stable/11/sys/dev/iwm/if_iwm_util.c	Thu Mar  1 06:34:21 2018	(r330201)
+++ stable/11/sys/dev/iwm/if_iwm_util.c	Thu Mar  1 06:34:48 2018	(r330202)
@@ -152,6 +152,7 @@ __FBSDID("$FreeBSD$");
 
 #include <dev/iwm/if_iwmreg.h>
 #include <dev/iwm/if_iwmvar.h>
+#include <dev/iwm/if_iwm_config.h>
 #include <dev/iwm/if_iwm_debug.h>
 #include <dev/iwm/if_iwm_binding.h>
 #include <dev/iwm/if_iwm_util.h>
@@ -485,4 +486,18 @@ iwm_dma_contig_free(struct iwm_dma_info *dma)
 		bus_dma_tag_destroy(dma->tag);
 		dma->tag = NULL;
 	}
+}
+
+boolean_t
+iwm_mvm_rx_diversity_allowed(struct iwm_softc *sc)
+{
+	if (num_of_ant(iwm_mvm_get_valid_rx_ant(sc)) == 1)
+		return FALSE;
+
+	/*
+	 * XXX Also return FALSE when SMPS (Spatial Multiplexing Powersave)
+	 *     is used on any vap (in the future).
+	 */
+
+	return TRUE;
 }

Modified: stable/11/sys/dev/iwm/if_iwm_util.h
==============================================================================
--- stable/11/sys/dev/iwm/if_iwm_util.h	Thu Mar  1 06:34:21 2018	(r330201)
+++ stable/11/sys/dev/iwm/if_iwm_util.h	Thu Mar  1 06:34:48 2018	(r330202)
@@ -120,6 +120,8 @@ extern	int iwm_dma_contig_alloc(bus_dma_tag_t tag, str
 				 bus_size_t size, bus_size_t alignment);
 extern	void iwm_dma_contig_free(struct iwm_dma_info *);
 
+extern	boolean_t iwm_mvm_rx_diversity_allowed(struct iwm_softc *sc);
+
 extern	uint8_t iwm_ridx2rate(struct ieee80211_rateset *rs, int ridx);
 
 static inline uint8_t