linux-kernel - Re: [PATCH V2] wlcore: sdio: Fixup power on/off sequence

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Date:   Wed, 16 Jan 2019 16:48:40 +0100
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Tony Lindgren <tony@...mide.com>, Kalle Valo <kvalo@...eaurora.org>
Cc:     Eyal Reizer <eyalr@...com>, linux-wireless@...r.kernel.org,
        Ricardo Salveti <rsalveti@...lveti.net>,
        Kishon Vijay Abraham I <kishon@...com>,
        Anders Roxell <anders.roxell@...aro.org>,
        John Stultz <john.stultz@...aro.org>,
        Jan Kiszka <jan.kiszka@....de>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-omap <linux-omap@...r.kernel.org>
Subject: Re: [PATCH V2] wlcore: sdio: Fixup power on/off sequence

On Wed, 16 Jan 2019 at 16:43, Tony Lindgren <tony@...mide.com> wrote:
>
> * Ulf Hansson <ulf.hansson@...aro.org> [190116 11:37]:
> > During "wlan-up", we are programming the FW into the WiFi-chip. However,
> > re-programming the FW doesn't work, unless a power cycle of the WiFi-chip
> > is made in-between the programmings.
> >
> > To conform to this requirement and to fix the regression in a simple way,
> > let's start by allowing that the SDIO card (WiFi-chip) may stay powered on
> > (runtime resumed) when wl12xx_sdio_power_off() returns. The intent with the
> > current code is to treat this scenario as an error, but unfortunate this
> > doesn't work as expected, so let's fix this.
> >
> > The other part is to guarantee that a power cycle of the SDIO card has been
> > completed when wl12xx_sdio_power_on() returns, as to allow the FW
> > programming to succeed. However, relying solely on runtime PM to deal with
> > this isn't sufficient. For example, userspace may prevent runtime suspend
> > via sysfs for the device that represents the SDIO card, leading to that the
> > mmc core also keeps it powered on. For this reason, let's instead do a
> > brute force power cycle in wl12xx_sdio_power_on().
> >
> > Fixes: 728a9dc61f13 ("wlcore: sdio: Fix flakey SDIO runtime PM handling")
> > Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
> > ---
> >
> > Changes in v2:
> >       - Keep the SDIO host claimed when calling mmc_hw_reset().
> >       - Add a fixes tag.
>
> This v2 version works for me as tested with:
>
> # while [ 1 ]; do ifconfig wlan0 down; ifconfig wlan0 up; done
> [  181.364990] wlcore: down
> [  182.116424] wlcore: firmware booted (Rev 6.3.10.0.141)
> [  182.151641] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
> [  182.166778] wlcore: down
> [  182.773132] wlcore: firmware booted (Rev 6.3.10.0.141)
> [  182.811096] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
> ...
>
> Thanks for fixing this issue properly, and feel free to add:
>
> Tested-by: Tony Lindgren <tony@...mide.com>

Thanks for testing, great news!

Before queuing this as fix, let's also see what the Hikey folkz thinks
of this. I have pinged Anders and he is currently running a test
suite.

Kalle, can you please tag this for stable as well?

Kind regards
Uffe