netdev - 答复: about [PATCH] net:usb:cdc_ncm: fix that tag Huawei devices as wwan

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Message-ID: <73FEE7778B75214796F3C8DE1ABE6DD66ED26CD3@szxema508-mbx.china.huawei.com>
Date:	Wed, 1 Jul 2015 00:49:01 +0000
From:	"Chenqi (jakio)" <cqi.chen@...wei.com>
To:	Bjørn Mork <bjorn@...k.no>
CC:	"torvalds@...ux-foundation.org" <torvalds@...ux-foundation.org>,
	"aleksander@...ksander.es" <aleksander@...ksander.es>,
	"dcbw@...hat.com" <dcbw@...hat.com>,
	"oliver@...kum.org" <oliver@...kum.org>,
	"ben.hutchings@...ethink.co.uk" <ben.hutchings@...ethink.co.uk>,
	"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"marcel@...tmann.org" <marcel@...tmann.org>,
	"xiaomao0213@...mail.com" <xiaomao0213@...mail.com>,
	Zhangyuhan <zhangyuhan@...wei.com>,
	Maqianni <maqianni@...wei.com>
Subject: 答复: about [PATCH] net:usb:cdc_ncm: fix that tag Huawei devices as wwan

Hi，bjorn,

Thanks for your kindly reply and providing so much info about linux wwan components!

We'll make a deep research on linux wwan architecture, maybe we can support it in the newly developing products.
About what you saying about "submit the patch formally", what steps should I do? Is there any documents about it?

Best Regards！
Jakio.chen

华为技术有限公司 Huawei Technologies Co., Ltd.

Phone: 18909297056
Email: cqi.chen@...wei.com
地址：西安市锦业一路软件大厦G座 邮编：710000

-----邮件原件-----
发件人: Bjørn Mork [mailto:bjorn@...k.no] 
发送时间: 2015年6月26日 17:21
收件人: Chenqi (jakio)
抄送: torvalds@...ux-foundation.org; aleksander@...ksander.es; dcbw@...hat.com; oliver@...kum.org; ben.hutchings@...ethink.co.uk; linux-usb@...r.kernel.org; netdev@...r.kernel.org; marcel@...tmann.org; xiaomao0213@...mail.com; Zhangyuhan
主题: Re: about [PATCH] net:usb:cdc_ncm: fix that tag Huawei devices as wwan

"Chenqi (jakio)" <cqi.chen@...wei.com> writes:

> Hi, All,
>
> I'm from Huawei Technologies Co., Ltd, working in mobile broadband 
> devices department.
>
> Huawei's broadband card don't support wwan in linux OS, there are 
> several historical reasons:
>
> 1.  Huawei produced dozens of broadband card types in past years, and 
> our customers/users integrate our products in many different OS 
> versions, We need give customer/user a continuous method to let them 
> use convenience.
>
> 2.  Wwan connection need application support, while we didn't test 
> them for compatibility.
>
> Meanwhile, we have provided serial port to let other existing 
> applications dial-up the connection
>
> I understand that you guys have some confusion why the Huawei 
> broadband cards support wwan in windows OS but not in linux OS with 
> the same device ID.  Since wwan standard is used firstly in windows 
> OS, when we pronounced to support this feature, wwan is not enabled in 
> linux.  So we keep the card's behavior in linux same as before.

The Linux kernel/drivers/userspace always will attempt to use hardware in the same way Windows use it, or at least as close as we are able to get.  The reason is simple: A billion (or whatever) Windows users is the best test lab you can get.

You may not agree with this strategy, but as a hardware vendor you have to expect it to happen.  The community will continue to develop support based on that assumption, even if you try to accommodate Linux by adding addiotional "Linux specific" features or modes.

> This wwan patch has great influence on our broadband cards, we have 
> tested many our broadband cards with this kernel version, and this 
> compatible issue is common.  So please approve our modification for 
> this problem.

If noone else has any comments or objections here, then I am certainly not going to object to the proposed patch.

Please go ahead and submit the patch formally.  I am going to keep my big mouth shut :)

> I think the root cause of this issue is this kernel version trait the 
> NCM as wwan devtype, maybe we can add a flag in usb descriptor in 
> future to indicate whether the device support wwan or not, then Huawei 
> can support wwan feature later for the newest product without 
> introducing compatible issues.
>
> BTW: if we want to join the usb-ethernet kernel evolution in linux, 
> which forum or organization should we join in?  We can participate in 
> it to avoid similar problems.

USB networking drivers are discussed, along with other network drivers, on the netdev@...r.kernel.org mailing list.  Preferable with a copy to the linux-usb@...r.kernel.org mailing list for USB expert review.

But as you point out above:  wwan connections need application support.
Userspace projects like ModemManager, oFono, libmbim, libqmi, umbim, uqmi and probably more, each have their own development forums/mailing lists.  This is where the most important part of the wwan developemt takes place.

Huawei have already made important contributions to the development of both Linux wwan drivers and userspace applications.  I am sure all those projects will appreciate any further help Huawei are able to offer.

Thanks a lot for your detailed introduction and explanation.

Bjørn