2019-01-08 20:31:47

by Sergey Matyukevich

Subject: [PATCH] mac80211: allow overriding HT STBC capabilities

From: Sergey Matyukevich <[email protected]>

Allow user to override STBC configuration for Rx and Tx spatial streams.
In practice RX/TX STBC settings can be modified using appropriate
options in wpa_supplicant configuration file:
tx_stbc=-1..1
rx_stbc=-1..3

This functionality has been added to wpa_supplicant in commit cdeea70f59d0.

In FullMAC case these STBC options are passed to drivers by cfg80211
connect callback in fields of cfg80211_connect_params structure.
However for mac80211 drivers, e.g. for mac80211_hwsim,
overrides for STBC settings are ignored.

The reason why RX/TX STBC capabilities are not modified for mac80211
drivers is as follows. All drivers need to specify supported HT/VHT
overrides explicitly: see ht_capa_mod_mask and vht_capa_mod_mask fields
of wiphy structure. Only supported overrides will be passed to drivers by
cfg80211_connect and cfg80211_mlme_assoc operations: see bitwise 'AND'
performed by cfg80211_oper_and_ht_capa and cfg80211_oper_and_vht_capa.

This commit adds RX/TX STBC HT capabilities to mac80211_ht_capa_mod_mask,
allowing their modifications, as well as applies requested STBC
modifications in function ieee80211_apply_htcap_overrides.

Signed-off-by: Sergey Matyukevich <[email protected]>
---
net/mac80211/ht.c | 8 ++++++++
net/mac80211/main.c | 2 ++
2 files changed, 10 insertions(+)

diff --git a/net/mac80211/ht.c b/net/mac80211/ht.c
index f849ea814993..e03c46ac8e4d 100644
--- a/net/mac80211/ht.c
+++ b/net/mac80211/ht.c
@@ -107,6 +107,14 @@ void ieee80211_apply_htcap_overrides(struct ieee80211_sub_if_data *sdata,
__check_htcap_enable(ht_capa, ht_capa_mask, ht_cap,
IEEE80211_HT_CAP_40MHZ_INTOLERANT);

+ /* Allow user to enable TX STBC bit */
+ __check_htcap_enable(ht_capa, ht_capa_mask, ht_cap,
+ IEEE80211_HT_CAP_TX_STBC);
+
+ /* Allow user to configure RX STBC bits */
+ if (ht_capa_mask->cap_info & IEEE80211_HT_CAP_RX_STBC)
+ ht_cap->cap |= ht_capa->cap_info & IEEE80211_HT_CAP_RX_STBC;
+
/* Allow user to decrease AMPDU factor */
if (ht_capa_mask->ampdu_params_info &
IEEE80211_HT_AMPDU_PARM_FACTOR) {
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 87a729926734..1114ee217bd6 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -478,6 +478,8 @@ static const struct ieee80211_ht_cap mac80211_ht_capa_mod_mask = {
IEEE80211_HT_CAP_MAX_AMSDU |
IEEE80211_HT_CAP_SGI_20 |
IEEE80211_HT_CAP_SGI_40 |
+ IEEE80211_HT_CAP_TX_STBC |
+ IEEE80211_HT_CAP_RX_STBC |
IEEE80211_HT_CAP_LDPC_CODING |
IEEE80211_HT_CAP_40MHZ_INTOLERANT),
.mcs = {
--
2.20.1

2019-01-14 09:10:09

by Sergey Matyukevich

Subject: Re: [PATCH] mac80211: allow overriding HT STBC capabilities

> From: Sergey Matyukevich <[email protected]>
>
> Allow user to override STBC configuration for Rx and Tx spatial streams.
> In practice RX/TX STBC settings can be modified using appropriate
> options in wpa_supplicant configuration file:
> tx_stbc=-1..1
> rx_stbc=-1..3
>
> This functionality has been added to wpa_supplicant in commit cdeea70f59d0.
>
> In FullMAC case these STBC options are passed to drivers by cfg80211
> connect callback in fields of cfg80211_connect_params structure.
> However for mac80211 drivers, e.g. for mac80211_hwsim,
> overrides for STBC settings are ignored.

...

> Signed-off-by: Sergey Matyukevich <[email protected]>
> ---
> net/mac80211/ht.c | 8 ++++++++
> net/mac80211/main.c | 2 ++
> 2 files changed, 10 insertions(+)

FWIW, the accompanying RFC patch extending STBC tests in hwsim hostapd test
suite has been posted to hostapd mailing list:

http://lists.infradead.org/pipermail/hostap/2019-January/039274.html

Regards,
Sergey