[MM] [PATCH 3/3] ZTE: improperly USSD-query encoding

[Alexander Orlov <alxorlov pochta ru>]

When I send an USSD query, it should be encoded to proper charset (UCS2
in my case). But it is not. Because of this USSD queries do not work at
all on my ZTE MF192 modem:

(ttyACM0): --> 'AT+CUSD=1,"*100#",15<CR>'
(ttyACM0): <-- '<CR><LF>ERROR<CR><LF>'

In git logs I have found this commit:
http://cgit.freedesktop.org/ModemManager/ModemManager/commit/plugins/mm-modem-zte.c?id=a57618b091faec24d22bfce5f384248c52cd2511

It disables hex encoding for USSD requests for all ZTE modems.

With that patch reversed, USSD works fine for me:

(ttyACM0): --> 'AT+CUSD=1,"002A0031003000300023",15<CR>'
(ttyACM0): <-- '<CR><LF>+CUSD: 0,"04110430043B0430043D0441003A003600390037002C0039003604400020041E043F043B0430044204300020043A043004400442043E04390020043F043E00200431002F043F002004420435043B04350444043E043D04430020002B00370034003900350037003600360030003100360036",72<CR><LF><CR><LF>OK<CR><LF>'
decode_ussd_response(): USSD data coding scheme 72

So, I think, ModemManager should match modem model and decide, if it
needs hex encodings. What do you think about this?

-- 
Alexander Orlov