Huawei/Vodafone K5160 in MBIM-mode, problems with dualstack

[Dan Williams]

On Thu, 2016-06-16 at 19:14 +0200, Thomas Schäfer wrote:
> Am 15.06.2016 um 21:41 schrieb Dan Williams:
> rther investigation, can you change this line in
> > 
> > connect_set_ready():
> > 
> >                 ctx->ip_type = ip_type;
> > 
> > to:
> > 
> > 		ctx->ip_type = MBIM_CONTEXT_IP_TYPE_IPV4V6;
> > 
> 
> With this setting the modem works in dualstack.

Thanks.  Looking at the MBIM spec, it says the modem needs to activate
the context type (10.5.12.1 MBIM_CID_CONNECT DESCRIPTION):

"On a Set request, the Host may specify an IP type to activate. If
MBIMContextIPTypeDefault is specified, the host does not care what IP
type is activated. If a value other than MBIMContextIPTypeDefault is
specified, the device must only activate that context.  When activated,
the device must return the appropriate IPType in response to a query
request."

I think the mistake MM is making is that it should only be reading
ip_type back in the response if MM passed MBIMContextIPTypeDefault
originally.  If MM passed an explicit context type (which it always
does) then the modem would error out if that type could not be
activated.

In this case, the modem's firmware is just being stupid...

Dan