Hi Avri, On Thu, Jun 11, 2015 at 3:29 PM, Altman, Avri <avri.altman@xxxxxxxxx> wrote: > > > -----Original Message----- > From: Julian Calaby [mailto:julian.calaby@xxxxxxxxx] > Sent: Thursday, June 11, 2015 6:55 AM > To: Grumbach, Emmanuel > Cc: Johannes Berg; linux-wireless; Altman, Avri > Subject: Re: [PATCH] mac80211: Disable U-APSD if connected to a SISO or non-HT AP > > Hi Emmanuel / Avri, > > On Wed, Jun 10, 2015 at 11:49 PM, Emmanuel Grumbach > <emmanuel.grumbach@xxxxxxxxx> wrote: >> From: Avri Altman <avri.altman@xxxxxxxxx> >> >> There are a few APs our there that advertise U-APSD >> capabilities but don't implement it right which leads to >> poor traffic. These APs don't support MIMO or don't even >> support HT. Use this heuristic to detect them and disable >> U-APSD accordingly. >> >> Signed-off-by: Avri Altman <avri.altman@xxxxxxxxx> >> Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@xxxxxxxxx> >> --- >> net/mac80211/scan.c | 25 +++++++++++++++++++++++++ >> 1 file changed, 25 insertions(+) >> >> diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c >> index 7bb6a93..3791c8a 100644 >> --- a/net/mac80211/scan.c >> +++ b/net/mac80211/scan.c >> @@ -39,6 +39,28 @@ void ieee80211_rx_bss_put(struct ieee80211_local *local, >> container_of((void *)bss, struct cfg80211_bss, priv)); >> } >> >> +/* >> + * An incompatible AP workaround: >> + * if the AP does not advertise MIMO capabilities disable U-APSD. >> + * iPhones, among others, advertise themselves as U-APSD capable when >> + * they aren't. Avoid connecting to those devices in U-APSD enabled. >> + */ >> +static bool broken_uapsd_workarounds(struct ieee802_11_elems *elems) > > Would a better name for this function be something like > is_uapsd_broken()? We're not actually working around anything here, > just checking whether it's broken or not. > > [Altman, Avri] Yeah - well, originally this was not the name, but a previous reviewer asked me to changed it to "workaround something...". > Actually it is a workaround of, among others, the iPhone 4/4s when SoftAP, they don't raise the > TIM in its Beacon even if it has data for us, therefore traffic is stuck. > We would prefer to identify those devices via their OUI, but currently this is not well defined. Fair enough then. As I see it, this isn't a workaround, it's just another test to ensure that uapsd can be supported. Thanks, -- Julian Calaby Email: julian.calaby@xxxxxxxxx Profile: http://www.google.com/profiles/julian.calaby/ -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
