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From: "Luis R. Rodriguez" <mcgrof@winlab.rutgers.edu>
Date: Wed, 22 Jul 2009 12:30:23 -0700
Message-ID: <43e72e890907221230m53109c3eqf388a2d987d8cdda@mail.gmail.com>
Subject: Re: [PATCH] compat-wireless-old: Fix problem with TX on amd64
To: Gao Lei <lei.alvin.gao@gmail.com>
Cc: linux-wireless@vger.kernel.org
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Sender: linux-wireless-owner@vger.kernel.org

On Wed, Jul 22, 2009 at 12:23 PM, Gao Lei<lei.alvin.gao@gmail.com> wrote:
> On amd64, the `ieee80211_tx_info' struct takes 56 bytes, thus cannot fit
> into skb's control buffer.
>
> The very first result is that nothing can be really sent out, because
> skb's next member `len' also gets cleared when doing:
>
>        info = IEEE80211_SKB_CB(skb);
>        memset(info, 0, sizeof(*info));
>
> A quick fix may be removing the TX control's sta pointer, since IMHO
> it's rarely used for now (the only place that I found was a function
> assigning values to it).
>
> It has been working well for me so far, but please let me know if
> there're better solutions. Thanks!
>
> Best regards,
> Gao Lei

Thanks, what kernel is this against BTW? Just so you know we should be
able to bring down compat-wireless down to 2.6.21 and maybe even
further now that we no longer are using the master netdev, which used
the multiqueue support added as of 2.6.27. Last I checked
compat-wireless now compiles on 2.6.25, but I never actually tried
loading it as I'm on ext4. So if you are on 2.6.25 or 2.6.26 you may
want to try out compat-wireless directly and see if to works. If you
are on 2.6.21..2.6.24 you can try adding backport support. I've added
a few files already for older kernel support based on our old
compat-wireless-old effort, so only the new stuff that mac80211 makes
use of should require backporting.

  Luis