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From:   Doug Anderson <dianders@chromium.org>
Date:   Mon, 7 Oct 2019 16:39:32 -0700
Message-ID: <CAD=FV=W-qh2NnDc-C1_Tki3=D7vzNGG2PgnZjCjdLU9gL68AxA@mail.gmail.com>
Subject: Re: [PATCH v2 0/2] mmc: core: Fix Marvell WiFi reset by adding SDIO
 API to replug card
To:     Ulf Hansson <ulf.hansson@linaro.org>
Cc:     Kalle Valo <kvalo@codeaurora.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Ganapathi Bhat <gbhat@marvell.com>,
        linux-wireless <linux-wireless@vger.kernel.org>,
        Andreas Fenkart <afenkart@gmail.com>,
        Brian Norris <briannorris@chromium.org>,
        Amitkumar Karwar <amitkarwar@gmail.com>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@lists.infradead.org>,
        Wolfram Sang <wsa+renesas@sang-engineering.com>,
        Nishant Sarmukadam <nishants@marvell.com>,
        netdev <netdev@vger.kernel.org>,
        Avri Altman <avri.altman@wdc.com>,
        "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Xinming Hu <huxinming820@gmail.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Kate Stewart <kstewart@linuxfoundation.org>
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Hi,

On Mon, Sep 16, 2019 at 2:25 AM Ulf Hansson <ulf.hansson@linaro.org> wrote:
>
> On Wed, 11 Sep 2019 at 23:26, Doug Anderson <dianders@chromium.org> wrote:
> >
> > Hi,
> >
> > On Thu, Jul 25, 2019 at 6:28 AM Ulf Hansson <ulf.hansson@linaro.org> wrote:
> > >
> > > On Mon, 22 Jul 2019 at 21:41, Douglas Anderson <dianders@chromium.org> wrote:
> > > >
> > > > As talked about in the thread at:
> > > >
> > > > http://lkml.kernel.org/r/CAD=FV=X7P2F1k_zwHc0mbtfk55-rucTz_GoDH=PL6zWqKYcpuw@mail.gmail.com
> > > >
> > > > ...when the Marvell WiFi card tries to reset itself it kills
> > > > Bluetooth.  It was observed that we could re-init the card properly by
> > > > unbinding / rebinding the host controller.  It was also observed that
> > > > in the downstream Chrome OS codebase the solution used was
> > > > mmc_remove_host() / mmc_add_host(), which is similar to the solution
> > > > in this series.
> > > >
> > > > So far I've only done testing of this series using the reset test
> > > > source that can be simulated via sysfs.  Specifically I ran this test:
> > > >
> > > > for i in $(seq 1000); do
> > > >   echo "LOOP $i --------"
> > > >   echo 1 > /sys/kernel/debug/mwifiex/mlan0/reset
> > > >
> > > >   while true; do
> > > >     if ! ping -w15 -c1 "${GW}" >/dev/null 2>&1; then
> > > >       fail=$(( fail + 1 ))
> > > >       echo "Fail WiFi ${fail}"
> > > >       if [[ ${fail} == 3 ]]; then
> > > >         exit 1
> > > >       fi
> > > >     else
> > > >       fail=0
> > > >       break
> > > >     fi
> > > >   done
> > > >
> > > >   hciconfig hci0 down
> > > >   sleep 1
> > > >   if ! hciconfig hci0 up; then
> > > >     echo "Fail BT"
> > > >     exit 1
> > > >   fi
> > > > done
> > > >
> > > > I ran this several times and got several hundred iterations each
> > > > before a failure.  When I saw failures:
> > > >
> > > > * Once I saw a "Fail BT"; manually resetting the card again fixed it.
> > > >   I didn't give it time to see if it would have detected this
> > > >   automatically.
> > > > * Once I saw the ping fail because (for some reason) my device only
> > > >   got an IPv6 address from my router and the IPv4 ping failed.  I
> > > >   changed my script to use 'ping6' to see if that would help.
> > > > * Once I saw the ping fail because the higher level network stack
> > > >   ("shill" in my case) seemed to crash.  A few minutes later the
> > > >   system recovered itself automatically.  https://crbug.com/984593 if
> > > >   you want more details.
> > > > * Sometimes while I was testing I saw "Fail WiFi 1" indicating a
> > > >   transitory failure.  Usually this was an association failure, but in
> > > >   one case I saw the device do "Firmware wakeup failed" after I
> > > >   triggered the reset.  This caused the driver to trigger a re-reset
> > > >   of itself which eventually recovered things.  This was good because
> > > >   it was an actual test of the normal reset flow (not the one
> > > >   triggered via sysfs).
> > > >
> > > > Changes in v2:
> > > > - s/routnine/routine (Brian Norris, Matthias Kaehlcke).
> > > > - s/contining/containing (Matthias Kaehlcke).
> > > > - Add Matthias Reviewed-by tag.
> > > > - Removed clear_bit() calls and old comment (Brian Norris).
> > > > - Explicit CC of Andreas Fenkart.
> > > > - Explicit CC of Brian Norris.
> > > > - Add "Fixes" pointing at the commit Brian talked about.
> > > > - Add Brian's Reviewed-by tag.
> > > >
> > > > Douglas Anderson (2):
> > > >   mmc: core: Add sdio_trigger_replug() API
> > > >   mwifiex: Make use of the new sdio_trigger_replug() API to reset
> > > >
> > > >  drivers/mmc/core/core.c                     | 28 +++++++++++++++++++--
> > > >  drivers/mmc/core/sdio_io.c                  | 20 +++++++++++++++
> > > >  drivers/net/wireless/marvell/mwifiex/sdio.c | 16 +-----------
> > > >  include/linux/mmc/host.h                    | 15 ++++++++++-
> > > >  include/linux/mmc/sdio_func.h               |  2 ++
> > > >  5 files changed, 63 insertions(+), 18 deletions(-)
> > > >
> > >
> > > Doug, thanks for sending this!
> > >
> > > As you know, I have been working on additional changes for SDIO
> > > suspend/resume (still WIP and not ready for sharing) and this series
> > > is related.
> > >
> > > The thing is, that even during system suspend/resume, synchronizations
> > > are needed between the different layers (mmc host, mmc core and
> > > sdio-funcs), which is common to the problem you want to solve.
> > >
> > > That said, I need to scratch my head a bit more before I can provide
> > > you some feedback on $subject series. Moreover, it's vacation period
> > > at my side so things are moving a bit slower. Please be patient.
> >
> > I had kinda forgotten about this series after we landed it locally in
> > Chrome OS, but I realized that it never got resolved upstream.  Any
> > chance your head has been sufficiently scratched and you're now happy
> > with $subject series?  ;-)
>
> It's still on my TODO list. Apologize for the delay, but I still need
> more time to look into it, possibly later this week.
>
> In any case, let's make sure we get this problem resolved for v5.5.

Hi Ulf.  It's your friendly pest, Doug, here to ask how things are going.  :-P


-Doug