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From:   Kalle Valo <kvalo@codeaurora.org>
To:     Tony Lindgren <tony@atomide.com>
Cc:     Ulf Hansson <ulf.hansson@linaro.org>,
        "Reizer\, Eyal" <eyalr@ti.com>,
        KISHON VIJAY ABRAHAM <kishon@ti.com>,
        "Mishol\, Guy" <guym@ti.com>,
        "linux-wireless\@vger.kernel.org" <linux-wireless@vger.kernel.org>,
        linux-omap <linux-omap@vger.kernel.org>,
        Anders Roxell <anders.roxell@linaro.org>,
        John Stultz <john.stultz@linaro.org>,
        Ricardo Salveti <rsalveti@rsalveti.net>
Subject: Re: [EXTERNAL] Re: [PATCH] wlcore: Fix bringing up wlan0 again if powered down briefly
References: <20181217164207.20081-1-tony@atomide.com>
        <CAPDyKFoLnNWsBfaUwqwL31J=zb0UOQjXUKi7Sj0AUsnNoC6bYg@mail.gmail.com>
        <20181218155439.GB6707@atomide.com>
        <CAPDyKFr2xx6fmdgjd10C1jekWg-yZPk32fGWEPO2PyexjofJ1A@mail.gmail.com>
        <20181220231401.GG6707@atomide.com>
        <c22e2ab61b494ea0852c0f4654fef92d@ti.com>
        <20181223160226.GK6707@atomide.com>
        <CAPDyKFoEOGACs4Wnm7UgKab2b1-7+v8+31DpC+p=8XxcQhSpcQ@mail.gmail.com>
        <20181228195903.GX6707@atomide.com>
        <CAPDyKFq9XmRueJEFKVb03hqLuoB84TGjrdvEjre46ezYbk_wgw@mail.gmail.com>
        <20190107151849.GC5544@atomide.com>
Date:   Mon, 07 Jan 2019 18:12:21 +0200
In-Reply-To: <20190107151849.GC5544@atomide.com> (Tony Lindgren's message of
        "Mon, 7 Jan 2019 07:18:49 -0800")
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Tony Lindgren <tony@atomide.com> writes:

> * Ulf Hansson <ulf.hansson@linaro.org> [190102 12:02]:
>>
>> However, if this is about an out-of-band IRQ line, instead of using
>> the SDIO IRQs on DAT1, I think management of that, belongs in the wlan
>> (or gpiochip) layers.
>
> Yes this can be handled at the gpiochip layer.
>
>> We have to distinguish if "down" has a strict requirement to power off
>> the wlan-chip.
>> 
>> For example, in "flight mode", is it okay to leave the wlan chip
>> powered on and thus potentially also having its radio part active?
>
> I don't know. If unsure, we should at least have that possibility
> available for future versions if needed. It might also help a bit
> with PM measurements :)

I don't know if there are any written rules but I have preferred that in
wireless drivers "ifconfig down" means that all power is turned off on
the device, at least this way user space can achive maximum power
savings. And there's also a simple way to start the firmware from clean
state, we all know how buggy firmwares are so I think that's important
as well.

-- 
Kalle Valo