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Subject: Re: [PATCH] ath9k: turn on btcoex_enable as default
From:   Kai Heng Feng <kai.heng.feng@canonical.com>
In-Reply-To: <7170e2d5-a59d-8260-fa8e-f02f583b773f@nbd.name>
Date:   Mon, 12 Feb 2018 12:15:53 +0800
Cc:     Kalle Valo <kvalo@codeaurora.org>, ath9k-devel@qca.qualcomm.com,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
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Message-Id: <6A0F65EF-A7C4-469F-8FAF-CBE314676237@canonical.com>
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To:     Felix Fietkau <nbd@nbd.name>
Sender: linux-kernel-owner@vger.kernel.org
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> On 10 Feb 2018, at 10:05 PM, Felix Fietkau <nbd@nbd.name> wrote:
> 
> On 2018-02-10 14:56, Kai Heng Feng wrote:
>> 
>>> On 9 Feb 2018, at 3:16 PM, Kalle Valo <kvalo@codeaurora.org> wrote:
>>> Sure, but we have to make sure that we don't create regressions on
>>> existing systems. For example, did you test this with any system which
>>> don't support btcoex? (just asking, haven't tested this myself)
>> 
>> No not really, but I will definitely test it.
>> The only module I have that uses ath9k is Dell’s DW1707.
>> How do I check if it support btcoex or not?
> I just reviewed the code again, and I am sure that we cannot merge this
> patch. Enabling the btcoex parameter makes the driver enable a whole
> bunch of code starting timers, listening to some GPIOs, etc.
> 
> On non-btcoex systems, some of those GPIOs might be floating or even
> connected to different things, which could cause a lot of undefined
> behavior.
> 
> This is simply too big a risk, so there absolutely needs to be a
> whitelist for systems that need this, otherwise it has to remain
> disabled by default.

So what information can we use to whitelist btcoex chips?
Can we get btcoex support status at ath9k probing?

Kai-Heng

> 
> - Felix