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;
/* Update global beacon interval time, this is needed for PS support */
rt2x00dev->beacon_int = bss_conf->beacon_int;
--
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