Re: [PATCH 2/6] wl1251: Use request_firmware_prefer_user() for loading NVS calibration data

From: Kalle Valo <kvalo@codeaurora.org>
To: "Pali Rohár" <pali.rohar@gmail.com>
Cc: Arend Van Spriel <arend.vanspriel@broadcom.com>,
	Ming Lei <ming.lei@canonical.com>,
	"Luis R. Rodriguez" <mcgrof@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	David Gnedt <david.gnedt@davizone.at>,
	Michal Kazior <michal.kazior@tieto.com>,
	Daniel Wagner <wagi@monom.org>, Tony Lindgren <tony@atomide.com>,
	Sebastian Reichel <sre@kernel.org>, Pavel Machek <pavel@ucw.cz>,
	Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>,
	Aaro Koskinen <aaro.koskinen@iki.fi>,
	Grazvydas Ignotas <notasas@gmail.com>,
	linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org,
	netdev@vger.kernel.org
Subject: Re: [PATCH 2/6] wl1251: Use request_firmware_prefer_user() for loading NVS calibration data
Date: Fri, 27 Jan 2017 17:23:07 +0200	[thread overview]
Message-ID: <87bmus5xyc.fsf@kamboji.qca.qualcomm.com> (raw)
In-Reply-To: <20170127131146.GI24223@pali> ("Pali \=\?utf-8\?Q\?Roh\=C3\=A1r\=22'\?\= \=\?utf-8\?Q\?s\?\= message of "Fri, 27 Jan 2017 14:11:46 +0100")

Pali Rohár <pali.rohar@gmail.com> writes:

> On Friday 27 January 2017 14:26:22 Kalle Valo wrote:
>> Pali Rohár <pali.rohar@gmail.com> writes:
>> 
>> > 2) It was already tested that example NVS data can be used for N900 e.g.
>> > for SSH connection. If real correct data are not available it is better
>> > to use at least those example (and probably log warning message) so user
>> > can connect via SSH and start investigating where is problem.
>> 
>> I disagree. Allowing default calibration data to be used can be
>> unnoticed by user and left her wondering why wifi works so badly.
>
> So there are only two options:
>
> 1) Disallow it and so these users will have non-working wifi.
>
> 2) Allow those data to be used as fallback mechanism.
>
> And personally I'm against 1) because it will break wifi support for
> *all* Nokia N900 devices right now.

All two of them? :)

But not working is exactly my point, if correct calibration data is not
available wifi should not work. And it's not only about functionality
problems, there's also the regulatory aspect.

>> > 3) If we do rename *now* we will totally break wifi support on Nokia
>> > N900.
>> 
>> Then the distro should fix that when updating the linux-firmware
>> packages. Can you provide details about the setup, what distro etc?
>
> Debian stable, Ubuntu LTSs 14.04, 16.04. 

You can run these out of box on N900?

> And I think that other LTS distributions contains that example nvs
> file too (I'm not going to verify others, but list will be probably
> long). Upgrading linux-firmware is against policy of those
> distributions. So no this is not an solution.

So instead we should workaround distro policies in kernel? Come on.

Seriously, just rename the file in linux-firmware and file a bug (with a
patch) to distros. If they don't fix the bug you just have to do a
custom hack for N900. But such is life.

-- 
Kalle Valo