diff mbox

[v2,1/2] ath10k: Fix bug in max. VHT A-MPDU size

Message ID 1380874630-14280-2-git-send-email-michal.kazior@tieto.com (mailing list archive)
State Not Applicable, archived
Headers show

Commit Message

Michal Kazior Oct. 4, 2013, 8:17 a.m. UTC 
From: Sujith Manoharan <c_manoha@qca.qualcomm.com>

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.

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
---
 drivers/net/wireless/ath/ath10k/mac.c |   14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

Comments

Kalle Valo Oct. 7, 2013, 4:33 p.m. UTC | #1 
Michal Kazior <michal.kazior@tieto.com> writes:

> From: Sujith Manoharan <c_manoha@qca.qualcomm.com>
>
> 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.
>
> Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
> Signed-off-by: Michal Kazior <michal.kazior@tieto.com>

I see warnings with this patch:

drivers/net/wireless/ath/ath10k/mac.c: In function 'ath10k_peer_assoc_h_vht':
drivers/net/wireless/ath/ath10k/mac.c:1049:179: warning: comparison of distinct pointer types lacks a cast [enabled by default]
drivers/net/wireless/ath/ath10k/mac.c:1049:30: error: incompatible types in comparison expression (different signedness)
drivers/net/wireless/ath/ath10k/mac.c:1042: WARNING: line over 80 characters
diff mbox

Patch

diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
index 8684e03..7e06e75 100644
--- a/drivers/net/wireless/ath/ath10k/mac.c
+++ b/drivers/net/wireless/ath/ath10k/mac.c
@@ -1033,14 +1033,26 @@  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,
+				 (1 << (IEEE80211_HT_MAX_AMPDU_FACTOR +
+					ampdu_factor)) - 1);
+
 	if (sta->bandwidth == IEEE80211_STA_RX_BW_80)
 		arg->peer_flags |= WMI_PEER_80MHZ;