From: "Bjørn Mork" <bjorn-yOkvZcmFvRU@public•gmane.org>
To: Oliver Neukum <oliver-GvhC2dPhHPQdnm+yROfE0A@public•gmane.org>
Cc: netdev-u79uwXL29TY76Z2rM5mHXA@public•gmane.org,
linux-usb-u79uwXL29TY76Z2rM5mHXA@public•gmane.org,
Greg Suarez <gsuarez-AKjrjAf1O7qe8kRwQpwjMg@public•gmane.org>,
Alexey Orishko
<alexey.orishko-0IS4wlFg1OjSUeElwK9/Pw@public•gmane.org>
Subject: Re: [PATCH net] net: cdc_ncm: workaround for missing CDC Union
Date: Fri, 18 Jan 2013 22:17:03 +0100 [thread overview]
Message-ID: <871udiur74.fsf@nemi.mork.no> (raw)
In-Reply-To: <22276933.xSGyXJfOvq-7ztolUikljGernLeA6q8OA@public.gmane.org> (Oliver Neukum's message of "Fri, 18 Jan 2013 20:11:25 +0100")
Oliver Neukum <oliver-GvhC2dPhHPQdnm+yROfE0A@public•gmane.org> writes:
> On Friday 18 January 2013 15:25:47 Bjørn Mork wrote:
>> Adding support for the MBIM mode in some Sierra Wireless devices.
>>
>> Some Sierra Wireless firmwares support CDC MBIM but have no CDC
>> Union funtional descriptor. This violates the MBIM specification,
>> but we can easily work around the bug by looking at the Interface
>> Association Descriptor instead. This is most likely what
>> Windows uses too, which explains how the firmware bug has gone
>> unnoticed until now.
>
> Should we do this for everything CDC?
I don't know. There are workarounds for missing CDC Union descriptors
on RNDIS devices in cdc_ether.c, but I have no idea if those devices in
provide an IAD instead. I don't think this bug is a very common.
MBIM devices are likely to have IADs because Microsoft let you skip some
of the more hairy vendor specific control message parts if you provide
one:
http://msdn.microsoft.com/en-us/library/windows/hardware/mbim-based-mobile-broadband-requirements-for-windows.aspx
But they should of course provide the CDC Union functional descriptor as
well, even if that is "just" a USB-IF requirement and not a Windows
requirement ;-)
Bjørn
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next prev parent reply other threads:[~2013-01-18 21:17 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-18 14:25 [PATCH net] net: cdc_ncm: workaround for missing CDC Union Bjørn Mork
[not found] ` <1358519147-10073-1-git-send-email-bjorn-yOkvZcmFvRU@public.gmane.org>
2013-01-18 19:11 ` Oliver Neukum
[not found] ` <22276933.xSGyXJfOvq-7ztolUikljGernLeA6q8OA@public.gmane.org>
2013-01-18 21:17 ` Bjørn Mork [this message]
2013-01-20 0:21 ` Alexey Orishko
[not found] ` <CAL_Kpj1B=_+eN3Y0n3d9_r4JoeHD2LQFSU+b+taCZL0G4icu6A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-01-21 8:31 ` Bjørn Mork
2013-01-21 14:08 ` Bjørn Mork
2013-01-21 14:47 ` Bjørn Mork
[not found] ` <87mww2y4ni.fsf-lbf33ChDnrE/G1V5fR+Y7Q@public.gmane.org>
2013-01-21 14:55 ` Oliver Neukum
2013-01-21 15:28 ` Bjørn Mork
[not found] ` <87ip6qy2q7.fsf-lbf33ChDnrE/G1V5fR+Y7Q@public.gmane.org>
2013-01-22 8:50 ` Oliver Neukum
2013-01-22 10:35 ` Bjørn Mork
2013-01-21 17:59 ` Alexey ORISHKO
2013-01-22 9:07 ` Oliver Neukum
2013-01-22 9:32 ` Oliver Neukum
2013-01-19 12:18 ` Bjørn Mork
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