From 711077a666f760b9c7c266725b4a5ec804248ebe Mon Sep 17 00:00:00 2001 From: Michal Kazior Date: Tue, 10 Feb 2015 12:48:44 +0100 Subject: [PATCH] mac80211: disable u-APSD queues by default commit aa75ebc275b2a91b193654a177daf900ad6703f0 upstream. Some APs experience problems when working with U-APSD. Decreasing the probability of that happening by using legacy mode for all ACs but VO isn't enough. Cisco 4410N originally forced us to enable VO by default only because it treated non-VO ACs as legacy. However some APs (notably Netgear R7000) silently reclassify packets to different ACs. Since u-APSD ACs require trigger frames for frame retrieval clients would never see some frames (e.g. ARP responses) or would fetch them accidentally after a long time. It makes little sense to enable u-APSD queues by default because it needs userspace applications to be aware of it to actually take advantage of the possible additional powersavings. Implicitly depending on driver autotrigger frame support doesn't make much sense. Signed-off-by: Michal Kazior Signed-off-by: Johannes Berg Signed-off-by: Ben Hutchings --- net/mac80211/ieee80211_i.h | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index cf7e7d337e49..8da371c5f583 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -54,13 +54,24 @@ struct ieee80211_local; #define TU_TO_EXP_TIME(x) (jiffies + usecs_to_jiffies((x) * 1024)) /* - * Some APs experience problems when working with U-APSD. Decrease the - * probability of that happening by using legacy mode for all ACs but VO. - * The AP that caused us trouble was a Cisco 4410N. It ignores our - * setting, and always treats non-VO ACs as legacy. + * Some APs experience problems when working with U-APSD. Decreasing the + * probability of that happening by using legacy mode for all ACs but VO isn't + * enough. + * + * Cisco 4410N originally forced us to enable VO by default only because it + * treated non-VO ACs as legacy. + * + * However some APs (notably Netgear R7000) silently reclassify packets to + * different ACs. Since u-APSD ACs require trigger frames for frame retrieval + * clients would never see some frames (e.g. ARP responses) or would fetch them + * accidentally after a long time. + * + * It makes little sense to enable u-APSD queues by default because it needs + * userspace applications to be aware of it to actually take advantage of the + * possible additional powersavings. Implicitly depending on driver autotrigger + * frame support doesn't make much sense. */ -#define IEEE80211_DEFAULT_UAPSD_QUEUES \ - IEEE80211_WMM_IE_STA_QOSINFO_AC_VO +#define IEEE80211_DEFAULT_UAPSD_QUEUES 0 #define IEEE80211_DEFAULT_MAX_SP_LEN \ IEEE80211_WMM_IE_STA_QOSINFO_SP_ALL -- 2.39.2