[ale] Modem identification and connecting

Alex Carver agcarver+ale at acarver.net
Sun Nov 10 14:22:26 EST 2013


I'll do my best but given that this has apparently been an ongoing
problem since 2007 across multiple distros it seems that no one has
quite figured out how to resolve it.  It appears I can have IrDA -or-
serial but not both in some systems.  In this case some digging suggests
an IO memory mapping issue.  The IrDA port tries to grab two addresses
(0x2f8 and 0x2e8) but there's already two ports in use by the serial
module (0x3f8-physport and 0x2f8-modem).  So the IrDA modules does a
power grab, shuffles addresses and IRQs around and poof, no more serial
ports.  The toshsat1800-irdasetup program identifies the IrDA chip and
sees three serial ports.  I'm not sure why it sees three though but it
doesn't appear that I can change the IO port addresses.

On 11/10/2013 09:57, Jim Kinney wrote:
> Cool! If you find out why the IrDA causes a conflict be sure to add to this
> thread, please. Oddball kernel issues are weird.
> On Nov 10, 2013 12:25 PM, "Alex Carver" <agcarver+ale at acarver.net> wrote:
> 
>> Nope, it was completely clean and so was the cardbus socket (the wifi
>> card works in both cardbus sockets).  Three hours of google searching
>> led me to blacklist the smsc_ircc2 module which woke up the serial ports
>> (both the on-board and the modem) and everything started working.
>> Somehow that module (used by the IrDA module) causes issues with serial
>> ports on many laptops.  I don't know why, that's probably more google
>> searching.  I don't need IrDA support (though it would be fun to play
>> with since I have several IrDA enabled devices) but it would be nice to
>> find out why smsc_ircc2 messes things up.
>>
>> On 11/10/2013 05:33, Jim Kinney wrote:
>>> Sounds like the modem is dead or maybe has some crud on the board. Try an
>>> electric cleaner spray.
>>> On Nov 9, 2013 3:47 PM, "Alex Carver" <agcarver+ale at acarver.net> wrote:
>>>
>>>> I'm tinkering with a cardbus modem I found in one of my hardware piles
>>>> (I'm still missing the actual cable but I know I have it here
>>>> somewhere).  Anyway, I'm trying to figure out the best way to see if
>>>> it's working (eg, responding to AT commands) but I can't quite seem to
>>>> get minicom to talk to it.  It's not a winmodem as far as I know.
>>>> According to dmesg, the pcmcia system sees the card, then serial_cs sees
>>>> the card and identifies it as a 16550A sittign on IRQ 3 0x3e8.  It
>>>> eventually gets assigned to /dev/ttyS2.
>>>>
>>>> So far nothing seems out of the ordinary but I just can't seem to get it
>>>> to respond to any basic commands (not even plain AT for which I should
>>>> see OK).  I know the cardbus system is working because I also have a
>>>> wireless network card in there and that's working fine.
>>>>
>>>> Ideas for probing and testing the modem?



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