K5160

[Markus Gothe]

Im pretty sure their NCM devices are able to send supported NTB formats. At least the Huawei driver indicates this.

They just change  pointers to the structs for 16/32 bit mode.

//MDen 2 mar 2016 09:51 skrev Bjørn Mork <bjorn at mork.no>:
>
> Bjørn Mork <bjorn at mork.no> writes:
>
> > The Windows driver sends a "reset function" request after the "get NTB
> > parameters" request.  The Linux driver doesn't do that.  Might make a
> > difference.  And it sends another "reset function" request just when
> > you'd think the setup was complete, restarting it all.  Don't know why
> > it does that.  Makes no sense to me.  But we could try it just for
> > completeness.
>
> I had to reread the spec to see if there is any reasons there for us to
> do this, but I still cannot see any.  Assuming the device is conforming
> to spec that is, which it clearly isn't.  So we can add the reset to
> replicate Windows behaviour in case some buggy firmware expects it, but
> that is the only reason.
>
> Rereading the NCM spec regarding device behaviour on "set interface" was
> far more interesting. I can recommend Huawei to review the section
> "7.2 Using Alternate Settings to Reset an NCM Function".  In short, the
> device is supposed to reset all relevant settins to default when the
> host selects altsetting 0.  And one of those defaults is:
>   "reset the NTB format to NTB-16"
>
> So there you have it.  The device should never operate in NTB-32 unless
> the host/driver explicitly selected that mode.
>
> But whatever.  If Windows selects NTB-32, then we might have to do the
> same. It will complicate the driver - unnecessarily IMHO.  But I am
> hoping that we can avoid configuring any vendor or devices specific
> quirks for this, though.  Let's cross fingers that Huawei at least have
> implemented a working "get NTB format" (required for devices supporting
> NTB-32), so that we can automatically detect devices refusing to operate
> in NTB-16 mode.
>
> Bjørn
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