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From:   Kalle Valo <kvalo@codeaurora.org>
To:     Tony Chuang <yhchuang@realtek.com>
Cc:     "linux-wireless\@vger.kernel.org" <linux-wireless@vger.kernel.org>,
        "briannorris\@chromium.org" <briannorris@chromium.org>,
        Arend Van Spriel <arend.vanspriel@broadcom.com>,
        Johannes Berg <johannes@sipsolutions.net>,
        "tamizhr\@codeaurora.org" <tamizhr@codeaurora.org>
Subject: Re: [PATCH v2 2/2] rtw88: add a debugfs entry to enable/disable coex mechanism
References: <20200309075852.11454-1-yhchuang@realtek.com>
        <20200309075852.11454-3-yhchuang@realtek.com>
        <877dzpu2lt.fsf@tynnyri.adurom.net>
        <33d4904b71a04ed8b0226ce07b037e05@realtek.com>
Date:   Fri, 13 Mar 2020 13:17:09 +0200
In-Reply-To: <33d4904b71a04ed8b0226ce07b037e05@realtek.com> (Tony Chuang's
        message of "Fri, 13 Mar 2020 02:23:38 +0000")
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Tony Chuang <yhchuang@realtek.com> writes:

> Kalle Valo <kvalo@codeaurora.org> :
>
>> <yhchuang@realtek.com> writes:
>> 
>> > From: Yan-Hsuan Chuang <yhchuang@realtek.com>
>> >
>> > Sometimes we need to stop the coex mechanism to debug, so that we
>> > can manually control the device through various outer commands.
>> > Hence, add a new debugfs coex_enable to allow us to enable/disable
>> > the coex mechanism when driver is running.
>> >
>> > To disable coex
>> > echo 0 > /sys/kernel/debug/ieee80211/phyX/rtw88/coex_enable
>> >
>> > To enable coex
>> > echo 1 > /sys/kernel/debug/ieee80211/phyX/rtw88/coex_enable
>> >
>> > To check coex dm is enabled or not
>> > cat /sys/kernel/debug/ieee80211/phyX/rtw88/coex_enable
>> 
>> I forgot, did we add a command to nl80211 for managing btcoex? At least
>> we have talking about that for years. Please check that first before
>> adding a debugfs interface for this.
>> 
>
> Yes, I found there was a thread [1] talking about adding a callback to
> enable/disable btcoex, but it seems not get applied eventually.

Too bad, I really think we should have at least enable/disable
functionality in nl80211. But if it's not there, I guess it's ok to have
yet another driver custom debugfs file :/

> And there's another thread [2] talking about add a btcoex subsystem.
> But seems like nobody can implement it cleanly in the host.
>
> I think adding btcoex subsystem could have a lot of pain since each
> vendor is using different mechanism controlling the btcoex, and it
> usually comes with RF related design which is difficult to write a common
> function to deal with all kinds of them.

Yeah, btcoex subsystem is a big challenge.

-- 
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