linux-kernel - Re: [PATCH 1/5] wifi: wilc1000: set preamble size to auto as default in wilc_init_fw

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Message-ID: <000e823e-ede1-408b-b8e1-fd9c1c73fd6e@bootlin.com>
Date: Thu, 18 Jan 2024 16:08:17 +0100
From: Alexis Lothoré <alexis.lothore@...tlin.com>
To: Kalle Valo <kvalo@...nel.org>
Cc: linux-wireless@...r.kernel.org, Ajay Singh <ajay.kathat@...rochip.com>,
 Claudiu Beznea <claudiu.beznea@...on.dev>,
 David Mosberger-Tang <davidm@...uge.net>,
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/5] wifi: wilc1000: set preamble size to auto as default
 in wilc_init_fw_config()

Hi Kalle,

On 1/18/24 10:31, Kalle Valo wrote:
> Alexis Lothoré <alexis.lothore@...tlin.com> wrote:
> 
>> From: Ajay Singh <ajay.kathat@...rochip.com>
>>
>> Changed the default value preamble to WILC_FW_PREAMBLE_AUTO in
>> wilc_init_fw_config().
>>
>> Signed-off-by: Ajay Singh <ajay.kathat@...rochip.com>
>> Signed-off-by: Alexis Lothoré <alexis.lothore@...tlin.com>
> 
> The commit message should always answer to the question "Why?". I can add that
> if you tell me what to add.

Yeah, sorry for the lack of description, I may have forgotten to update this
one. I suggest to update it with the following message:

"WILC driver currently applies some default configuration whenever the firmware
is initialized, and sets the default preamble size to short. However, despite
this passed option, firmware is also able to successfully connect to access
points only using long preamble, so this setting does not really enforce short
preambles and is misleading regarding applied configuration.

Update default configuration and make it match the firmware behavior by passing
the existing WILC_FW_PREAMBLE_AUTO value (2 instead of 0). The updated setting
does not really alter firmware behavior since it is still capable to connect to
both short preamble and long preamble access points, but at list the setting now
expresses for real the corresponding firmware behavior"

To give a bit of context around this one: I do not have access to the firmware
internals, I just took the patch from Ajay and I merely did some tests around it
with multiple APs (basically, making a WILC STA connect and ping the AP), and
ensured with wireshark to get at least one AP be really "locked" with long
preamble, with WILC managing to connect to it.

Thanks,

Alexis

-- 
Alexis Lothoré, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com