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From:   Kalle Valo <kvalo@codeaurora.org>
To:     Ulf Hansson <ulf.hansson@linaro.org>
Cc:     Tony Lindgren <tony@atomide.com>, Eyal Reizer <eyalr@ti.com>,
        linux-wireless@vger.kernel.org,
        Ricardo Salveti <rsalveti@rsalveti.net>,
        Kishon Vijay Abraham I <kishon@ti.com>,
        Anders Roxell <anders.roxell@linaro.org>,
        John Stultz <john.stultz@linaro.org>,
        Jan Kiszka <jan.kiszka@web.de>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-omap <linux-omap@vger.kernel.org>
Subject: Re: [PATCH V2] wlcore: sdio: Fixup power on/off sequence
References: <20190116113723.15668-1-ulf.hansson@linaro.org>
        <20190116154311.GP5544@atomide.com>
        <CAPDyKFpAc=xSsLKgMm-2H4WkD34ieRS91wH4GbwD=GH01-pt3A@mail.gmail.com>
Date:   Wed, 16 Jan 2019 18:18:00 +0200
In-Reply-To: <CAPDyKFpAc=xSsLKgMm-2H4WkD34ieRS91wH4GbwD=GH01-pt3A@mail.gmail.com>
        (Ulf Hansson's message of "Wed, 16 Jan 2019 16:48:40 +0100")
Message-ID: <87muo04lvr.fsf@codeaurora.org>
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Ulf Hansson <ulf.hansson@linaro.org> writes:

> On Wed, 16 Jan 2019 at 16:43, Tony Lindgren <tony@atomide.com> wrote:
>>
>> * Ulf Hansson <ulf.hansson@linaro.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@linaro.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@atomide.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?

Ok, I'll queue this for 5.0 (but wait for testing feedback at least a
day) and add:

Cc: <stable@vger.kernel.org>

-- 
Kalle Valo