From: Sujith Manoharan <c_manoha@xxxxxxxxxxxxxxxx>
For VHT peers, the maximum A-MPDU size has to be calculated
from the VHT capabilities element and not the HT-cap. The formula
is the same, but a higher value is used in VHT, allowing larger
aggregates to be transmitted.
The patch contains a workaround for some Netgear/Linksys APs that
report Rx A-MPDU factor incorrectly.
Tested-by: Kalle Valo <kvalo@xxxxxxxxxxxxxxxx>
Signed-off-by: Sujith Manoharan <c_manoha@xxxxxxxxxxxxxxxx>
Signed-off-by: Michal Kazior <michal.kazior@xxxxxxxxx>
---
v3:
* fix lines over 80 chars (Kalle)
* fix max() cast warning (Kalle)
* add Tested-by
drivers/net/wireless/ath/ath10k/mac.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
index 4b7c949..049eca2 100644
--- a/drivers/net/wireless/ath/ath10k/mac.c
+++ b/drivers/net/wireless/ath/ath10k/mac.c
@@ -1033,14 +1033,27 @@ static void ath10k_peer_assoc_h_vht(struct ath10k *ar,
struct wmi_peer_assoc_complete_arg *arg)
{
const struct ieee80211_sta_vht_cap *vht_cap = &sta->vht_cap;
+ u8 ampdu_factor;
if (!vht_cap->vht_supported)
return;
arg->peer_flags |= WMI_PEER_VHT;
-
arg->peer_vht_caps = vht_cap->cap;
+
+ ampdu_factor = (vht_cap->cap &
+ IEEE80211_VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_MASK) >>
+ IEEE80211_VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_SHIFT;
+
+ /* Workaround: Some Netgear/Linksys 11ac APs set Rx A-MPDU factor to
+ * zero in VHT IE. Using it would result in degraded throughput.
+ * arg->peer_max_mpdu at this point contains HT max_mpdu so keep
+ * it if VHT max_mpdu is smaller. */
+ arg->peer_max_mpdu = max(arg->peer_max_mpdu,
+ (1U << (IEEE80211_HT_MAX_AMPDU_FACTOR +
+ ampdu_factor)) - 1);
+
if (sta->bandwidth == IEEE80211_STA_RX_BW_80)
arg->peer_flags |= WMI_PEER_80MHZ;
--
1.8.4.rc3
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