Re: Flush scan list on resume

Tony Espy wrote:
Dan Williams wrote:
On Wed, 2009-02-04 at 15:40 -0800, Howard Chu wrote:
OK. I suggest a compromise then, since fetching kernel time will also be
expensive if done frequently - just fetch it at driver load and resume time,
and store it as a<base>  in the driver. Cache entries then store base+jiffy.
This allows cache stamps to continue to be cheap, but also solves the
sleep/resume mismatch.
Yeah, that might work.  Want to whip up a quick patch we can use for
further discussion?

Will look into it.

I still think simple ( ie. either have mac80211 handle the expiration or
flush of scan results on resume ) wins out over the more complicated
approach of having the connection manager handle expiration of older
scan results.

Also a mobile device ( eg. a netbook or OLPC ) could be moving relative
to the same set of access points while in S3 ( ie. within a single
office and/or building ), and that the cached scan results after resume
could reflect inaccurate relative signal strengths of the the APs.  This
could effect roaming performance.

Yeah, good point. This is also trivial to implement - just call ieee80211_rx_bss_list_deinit(local) in pm.c: __iee80211_suspend(). I'm going to play with this approach first.

  -- Howard Chu
  CTO, Symas Corp. 
  Director, Highland Sun
  Chief Architect, OpenLDAP

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