Re: [PATCH v2 0/2] mmc: core: Fix Marvell WiFi reset by adding SDIO API to replug card

From: Doug Anderson
Date: Wed Sep 11 2019 - 17:26:23 EST


Hi,

On Thu, Jul 25, 2019 at 6:28 AM Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote:
>
> On Mon, 22 Jul 2019 at 21:41, Douglas Anderson <dianders@xxxxxxxxxxxx> wrote:
> >
> > As talked about in the thread at:
> >
> > http://lkml.kernel.org/r/CAD=FV=X7P2F1k_zwHc0mbtfk55-rucTz_GoDH=PL6zWqKYcpuw@xxxxxxxxxxxxxx
> >
> > ...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? ;-)

-Doug