Re: [PATCH v2 1/5] mac80211: fix race with suspend and dynamic_ps_disable_work

[Johannes Berg <johannes@sipsolutions.net>]

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On Thu, 2009-12-24 at 15:26 -0500, Luis R. Rodriguez wrote:
> When mac80211 suspends it calls a driver's suspend callback
> as a last step and after that the driver assumes no calls will
> be made to it until we resume and its start callback is kicked.
> If such calls are made, however, suspend can end up throwing
> hardware in an unexpected state and making the device unusable
> upon resume.
> 
> Fix this by preventing mac80211 to schedule dynamic_ps_disable_work
> by checking for when mac80211 starts to suspend and starts
> quiescing. Frames should be allowed to go through though as
> that is part of the quiescing steps and we do not flush the
> mac80211 workqueue since it was already done towards the
> beginning of suspend cycle.
> 
> The other mac80211 issue will be hanled in the next patch.
> 
> For further details see refer to the thread:
> 
> http://marc.info/?t=126144866100001&r=1&w=2
> 
> Cc: stable@kernel.org
> Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>

Looks fine to me.

Acked-by: Johannes Berg <johannes@sipsolutions.net>

> ---
>  net/mac80211/tx.c |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> index ac48c86..42bfd97 100644
> --- a/net/mac80211/tx.c
> +++ b/net/mac80211/tx.c
> @@ -1418,6 +1418,10 @@ static bool need_dynamic_ps(struct
> ieee80211_local *local)
>  	if (!local->ps_sdata)
>  		return false;
>  
> +	/* No point if we're going to suspend */
> +	if (local->quiescing)
> +		return false;
> +
>  	return true;
>  }
>  


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