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Date:      Sun, 7 Jan 2007 16:52:14 +0100
From:      Max Laier <max@love2party.net>
To:        freebsd-hackers@freebsd.org
Cc:        Massimo Lusetti <mlusetti@gmail.com>, Benjamin Close <Benjamin.Close@clearchain.com>, Florent Thoumie <flz@freebsd.org>, freebsd-drivers@freebsd.org, Attilio Rao <attilio@freebsd.org>, damien.bergamini@free.fr, sam@freebsd.org, gabor@freebsd.org
Subject:   Re: Updated Driver for 3945ABG Intel 3945ABG Wireless LAN controller
Message-ID:  <200701071652.24674.max@love2party.net>
In-Reply-To: <45A0F739.3030202@clearchain.com>
References:  <459E6477.2010508@clearchain.com> <a6647e120701050844u49b3f867xcbc0235e50871578@mail.gmail.com> <45A0F739.3030202@clearchain.com>

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On Sunday 07 January 2007 14:35, Benjamin Close wrote:
> Massimo Lusetti wrote:
> > On 1/5/07, Max Laier <max@love2party.net> wrote:
> >> Thoughts?  Volunteers?
> >
> > I can say that the first attempt still running fine here on my laptop
> > on a -STABLE as of yesterday. I use it on a daily basis without any
> > glitch. I must say i don't do or tried to do nothing special or
> > network intensive job, but for reading emails, doing a lot of ssh and
> > http/https the drivers is working smoothly.
> >
> > I will try to compile this new one on my stable during the week end
> > and will see on Monday how it will perform on my office wi-lan.
> >
> > For the records: my wpi doesn't still work on OpenBSD-current cause
> > it's integrated and the switch used to turn it on seems an acpi one
> > which OpenBSD doesn't attach very well yet.
>
> Hi Folks,
>     I did the port as my searching led me to believe that progress on a
> driver had stagnated.
> Port 1: was done by Damien himself
> (http://lists.freebsd.org/pipermail/freebsd-mobile/2006-July/008768.htm
>l) Port 2: was an updated version by Daminen:
> http://osdir.com/ml/freebsd-hackers@freebsd.org/msg58154.html
>             which seems to be duplicated here:
> http://people.freebsd.org/~flz/local/wpi/
> (http://www.mail-archive.com/freebsd-net@freebsd.org/msg20710.html)
> With version 2 being minor bug fixes to version 1 to try and get it
> working. Since then the driver has come a long way in netbsd with the
> FreeBSD version just getting older.
>
> To others working on a wpi driver, please post something indicating
> what you've done and even a sample of what your up to so we can one
> build one driver that just works. I also did the driver port as
> everything I found failed to work on a 64bit kernel, most the time
> wouldn't even compile.
>
> I'm happy to try and maintain this driver. I have the hardware.

Excellent!

> The main bugs I know about in this driver port are:
>
> * The use of the iee80211_amrr code
> The files exist in -current in /usr/src/sys/net80211 but the required
> symbols are not in a GENERIC kernel build. There is a wlan_amrr module
> which uses this code, though I'm not sure how to make use of this, it
> appears a simple dependency on the module is not enough. The use of the
> 80211_amrr code also means that use under -stable requires quite a bit
> more work as Rink pointed out.
>
>  * Bus resource allocation issues
> Mainly related to:  "bus_dmamem_alloc failed to align memory properly."
> I'm hoping Mike
> (http://lists.freebsd.org/pipermail/freebsd-stable/2006-June/026262.htm
>l) might be able to help resolve these.
>
> These allocation issues are caused while allocating of the rx & tx ring
> buffers - which if they are broken explain why things don't work.
> I'm still coming to grips to how the whole bus_dma_tag_create works.
> The Netbsd bus_dma_map_alloc seems much more intuitive.
> I've found if the module failed the first time, unloading it, then
> reloading it would often make the allocation issues disappear and the
> driver just work.
> Though I've also found sometimes that even though the allocation issues
> are reported, things still work, I'm guessing the alignment is pulled
> into line by higher levels of bus_dma.
>
> * ifconfig down causes timeouts reseting the tx ring
> I'm still chasing the cause of this. It seems non critical as the
> driver still works with an ifconfig up
>
> * Watch dog timer uses an obsolete interface
> I'm looking into the correct way to do watchdog timing

I have patches for iwi(4) somewhere and should finally get to doing=20
something with them ...

> * A lock order reversal in wpi_intr
> lock order reversal:
>  1st 0xffffffff812d9e20 wpi0 (network driver) @ if_wpi.c:1554
>   2nd 0xffffff003cee32f0 radix node head (radix node head) @
> net/route.c:147 KDB: stack backtrace:
>   db_trace_self_wrapper() at db_trace_self_wrapper+0x3a
>   witness_checkorder() at witness_checkorder+0x4f9
>   _mtx_lock_flags() at _mtx_lock_flags+0x75
>   rtalloc1() at rtalloc1+0x7a
>   arplookup() at arplookup+0x5c
>   arpintr() at arpintr+0x255
>   ether_demux() at ether_demux+0x2d3
>   ether_input() at ether_input+0x1e9
>   ieee80211_input() at ieee80211_input+0xd05
>   wpi_intr() at wpi_intr+0x9d7
>   ithread_loop() at ithread_loop+0xfe
>   fork_exit() at fork_exit+0xaa
>   fork_trampoline() at fork_trampoline+0xe
>   --- trap 0, rip =3D 0, rsp =3D 0xffffffffa0698d40, rbp =3D 0 ---

This one looks like the same issue as if_iwi.c, 1.43:=20
http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/dev/iwi/if_iwi.c#rev1.43

i.e. just drop the driver lock when calling back into the (net80211)=20
stack.  There is some discussion about how the "ic" is protected, but for=20
now dropping the lock is the right thing to do.

> For those wishing to help debug the driver and get it working, I've
> posted a new version
> http://www.clearchain.com/~benjsc/download/20070107-wpi-freebsd.tar.gz

Your box seems to have a reasonable uptime.  Is that right, or should I=20
continue to mirror your tarballs?

> To help debug:
>
>     kldload wpi_ucode
>     kldload if_wpi
>     wlandebug -i wpi0 0xffffff   (I've included a copy of the -current
> tool to save having to checkout the tree)
>     sysctl debug.wpi=3D10        (Debug levels are explained in if_wpi.c)
>     ifconfig wpi0 up
>     ... wait 30 seconds then...
>     ifconfig wpi0 down
>
>     Then put /var/log/messages somewhere on the web & let me know
>
> This will dump lots of debug info to syslog but should help me work out
> whats happening. If the driver works for you, stick to debug level 5
> max, else you'll be bombarded with logs. I'll try to install FBSD 32
> -current & -stable (32/64) on the laptop in the next week to see what
> might be different. ANY feedback is helpful.
>
> Finally, for those who see "rx tail flags error xxx" this is caused by
> a 802.11 frame with an invalid CRC. Hence seeing the occasional one
> (with debug level 4 or higher) is quiet normal. If you see floods of
> them then chances are the rx ring is really out of alignment and things
> will just be busted.

=2D-=20
/"\  Best regards,                      | mlaier@freebsd.org
\ /  Max Laier                          | ICQ #67774661
 X   http://pf4freebsd.love2party.net/  | mlaier@EFnet
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