[OpenWrt-Devel] [PATCH] comgt: add ncm proto support

John Crispin blogic at openwrt.org
Wed Oct 8 12:42:39 EDT 2014


hi conor

On 08/10/2014 17:27, Conor O'Gorman wrote:
> 
> 
> On 08/10/14 11:00, John Crispin wrote:
>> the e3267 that sami sent me works with this proto, but i am
>> failing to get a DHCP addr. could someone with a ncm dongle
>> please try this patch on top of latest trunk please and tell me
>> if they are getting a dhcp addr ?
> 
> I had a similar problem with a Huawei device. It worked after
> removing some zero padding in the ncm driver.
> 
> In cdc_ncm.c, cdc_ncm_fill_tx_frame(), towards the end there is
> handling for Zero Length Packets (ZLP) and padding short packets. I
> removed the padding, and it worked. Are you testing 3.10 or 3.14?
> It's changed ever so slightly between them.
> 

3.14, will have a look at it tomorrow.

> I am somewhat confused by the comment. It won't pad out short
> packets, but does make shortish packets long.

sounds weird indeed

	John




> 
> FYI: /* * If collected data size is less or equal
> CDC_NCM_MIN_TX_PKT bytes, * we send buffers as it is. If we get
> more data, it would be more * efficient for USB HS mobile device
> with DMA engine to receive a full * size NTB, than canceling DMA
> transfer and receiving a short packet. */ if (skb_out->len >
> CDC_NCM_MIN_TX_PKT) /* final zero padding */
> 
> 
> Conor _______________________________________________ openwrt-devel
> mailing list openwrt-devel at lists.openwrt.org 
> https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
> 
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