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Date:   Sat, 12 Feb 2022 09:48:09 -0600
From:   Seth Forshee <sforshee@kernel.org>
To:     Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc:     wireless-regdb@lists.infradead.org, linux-wireless@vger.kernel.org
Subject: Re: [PATCH] wireless-regdb: Update regulatory rules for China (CN)
Message-ID: <YgfWuV8E+xHZGeqh@ubuntu-x1>
References: <9a460b85-4e1b-40b2-8691-3f999331c76b@www.fastmail.com>
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On Fri, Feb 04, 2022 at 03:19:29PM +0000, Jiaxun Yang wrote:
> China had updated regulations on ISM frequencies by
> "工信部无〔2021〕129号".
> 
> The new regulation effectives from Jan 1 2022.
> 
> Update regdb accroading to it's attachment "2400MHz、5100MHz
> 和 5800MHz 频段无线电发射设备射频技术要求".
> 
> Announcement: https://wap.miit.gov.cn/zwgk/zcwj/wjfb/tz/art/2021/art_e4ae71252eab42928daf0ea620976e4e.html
> Attachment: https://wap.miit.gov.cn/cms_files/filemanager/1226211233/attach/20219/d125301b13454551b698ff5afa49ca28.pdf
> 
> Those documents are only available in Chinese.
> 
> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>

Thanks for the patch. I'm looking at a machine translation of the
document, and based on that I think one change needs to be made, see
below. If something was mistranslated or if I misunderstood, please let
me know.

> ---
>  db.txt | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/db.txt b/db.txt
> index 6dbda3c..e6fd657 100644
> --- a/db.txt
> +++ b/db.txt
> @@ -346,11 +346,12 @@ country CL: DFS-JP
>  	(5250 - 5330 @ 80), (20), DFS, AUTO-BW
>  	(5735 - 5835 @ 80), (20)
>  
> +# Source:
> +# https://wap.miit.gov.cn/cms_files/filemanager/1226211233/attach/20219/d125301b13454551b698ff5afa49ca28.pdf
>  country CN: DFS-FCC
> -	(2402 - 2482 @ 40), (20)
> -	(5170 - 5250 @ 80), (23), AUTO-BW
> -	(5250 - 5330 @ 80), (23), DFS, AUTO-BW
> -	(5735 - 5835 @ 80), (30)
> +	(2400 - 2483.5 @ 40), (20)
> +	(5150 - 5350 @ 80), (23), DFS, AUTO-BW

It looks like this range requires TPC, and if TPC is not supported the
max EIRP needs to be lowered by 3 dBm. Since Linux does not support TPC,
we need to reduce this power limit to 20 dBm.

Thanks,
Seth

> +	(5725 - 5850 @ 80), (33)
>  	# 60 GHz band channels 1,4: 28dBm, channels 2,3: 44dBm
>  	# ref: http://www.miit.gov.cn/n11293472/n11505629/n11506593/n11960250/n11960606/n11960700/n12330791.files/n12330790.pdf
>  	(57240 - 59400 @ 2160), (28)
> -- 
> 2.34.1.windows.1