Re: [PATCH v1 1/3] usb: gadget: NCM: RX function support multiple NDPs

From: Jim Baxter <jim_baxter@mentor.com>
To: "Bjørn Mork" <bjorn@mork.no>
Cc: Felipe Balbi <balbi@ti.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	<linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	David Laight <David.Laight@ACULAB.COM>, <netdev@vger.kernel.org>
Subject: Re: [PATCH v1 1/3] usb: gadget: NCM: RX function support multiple NDPs
Date: Fri, 30 May 2014 12:45:48 +0100	[thread overview]
Message-ID: <53886F6C.7090509@mentor.com> (raw)
In-Reply-To: <87d2ewbejv.fsf@nemi.mork.no>

On 29/05/14 19:55, Bjørn Mork wrote:
> Jim Baxter <jim_baxter@mentor.com> writes:
> 
>> The NDP was ignoring the wNextNdpIndex in the NDP which
>> means that NTBs containing multiple NDPs would have missed
>> frames.
> 
> Well, just for the record: I believe this field was meant to be reserved
> and always 0 in the CDC NCM spec.  Table 3-3, describing 16bit NDPs,
> says so.  But reading the spec now, I noticed that there is an
> inconsistency between table 3-3 and table 3-4 describing 32bit NDPs.  It
> looks like the field is not reserved in the 32bit version.
> 
> I am pretty sure that is a specification error, but I guess it doesn't
> harm to implement the support anyway.  And it paves the way for an MBIM
> gadget :-)
> 
> 
> 
> 
> Bjørn
> 

Yes I was looking at Figure 3-1, Figure 3-2 which all state it is a
link. I must have been reading Table 3-4.

I am glad to see it helps with the MBIM specification :-) .

Jim