On Fri, Jun 1, 2012 at 9:37 AM, Ivo Van Doorn <ivdoorn@xxxxxxxxx> wrote: > Hi, > >> On Wed, May 9, 2012 at 11:08 AM, Johannes Berg >> <johannes@xxxxxxxxxxxxxxxx> wrote: >>> From: Johannes Berg <johannes.berg@xxxxxxxxx> >>> >>> Some drivers (iwlegacy, iwlwifi and rt2x00) today use the >>> bss_conf.last_tsf value. By itself though that value is >>> completely worthless since it may be ancient. What really >>> is needed is synchronisation between some device time and >>> the TSF. >>> >>> To clarify this, rename bss_conf.last_tsf to sync_tsf and >>> add sync_device_ts which is obtained from rx_status which >>> gets a new field device_timestamp for this purpose. This >>> is intentionally not using the mactime field since that >>> is used for other things and in IBSS is expected to sync >>> with the IBSS's TSF which isn't necessarily true for the >>> device timestamp. >>> >>> Also, since we have the information and it's useful even >>> before the connection has been established, give all the >>> timing details to the driver before authenticating. >>> >>> Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx> >>> --- >>> I note that rt2x00 is completely broken since it mixes last_tsf (now >>> sync_tsf) with jiffies ... what?? >> >> Thanks for coming up with this Johannes, that looks indeed strange. >> >> Ivo, that was introduced with your "rt2x00: Add autowake support for >> USB hardware" patch as far as I can tell. >> >> Since the last_beacon value is updated within rt2x00 already we should >> be able to just remove the assignment in rt2x00lib_config_erp. Ivo, could >> you please recheck? >> >> This would also remove rt2x00's dependency on the last_tsf >> field as provided by mac80211. >> >> Thanks, >> Helmut >> >> diff --git a/drivers/net/wireless/rt2x00/rt2x00config.c >> b/drivers/net/wireless/rt2x00/rt2x00config.c >> index 96db933..b2d2ad3 100644 >> --- a/drivers/net/wireless/rt2x00/rt2x00config.c >> +++ b/drivers/net/wireless/rt2x00/rt2x00config.c >> @@ -102,7 +102,6 @@ void rt2x00lib_config_erp(struct rt2x00_dev *rt2x00dev, >> >> /* Update the AID, this is needed for dynamic PS support */ >> rt2x00dev->aid = bss_conf->assoc ? bss_conf->aid : 0; >> - rt2x00dev->last_beacon = bss_conf->last_tsf; > > Can't access the code right now, is the last_beacon initialized somewhere else? > because I do assume we need the value somewhere? Yup, it's set in two code paths. One is within rt2x00 where last_beacon is set to jiffies. The other one is here where it is set to last_tsf which is not derived from jiffies at all :D Helmut -- 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
