Re: HiSax modem emulation: X.75-connection brakes down

Hello Jens,

Am 26.10.2012 16:08, schrieb Jens Bürger:
> Hi there,
> 
> I have two PCs running, each connected to a ISDN-PBX (Octopus E Modell
> 300/800).
> 
> PC Bo: HFC PCI card, Debian squeeze
> PC Ket: Windows with a VM (Debian squeeze), HFC-USB
> 
> I'm connecting to the PBX using the modememulation to do stuff over a
> X.75-connection.
> I'm using the following process:
> 
> -> minicom -D /dev/ttyI0
> Initialize the emulation
> -> socat
> for access via TCP/IP
> -> screen and telnet
> to connect and have a running session when no one is logged in.
> 
> As long as there is a running connection, the PBX sends data to the PC
> once a minute, so there should'nt be any idle-timeout-issue.
> 
> While this construct runs fine on PC Bo, I have some problems with PC Ket.
> 
> First: I didn't manage to get isdnlog and Co running, even the ttyI*'s
> were not created. I'm creating the device manually with
> mknod -m 660 /dev/ttyI0 c 43 0
> 
> Second: HiSax doesn't fully come up. Even after a restart, about every
> second boot the recognition of the card seems not to run right and the
> following lines in dmesg are MISSING:
> HiSax: Card 1 Protocol EDSS1 Id=hfc_usb0 (0)
> HiSax: DSS1 Rev. 2.32.2.3
> HiSax: 2 channels added
> HiSax: MAX_WAITING_CALLS added
> 
> Re-loading the hfc_usb or hisax-kernelmodules doesn't really help then,
> the only thing I can do is to reboot the machine.
> 
> Third: The most disturbing issue is: after a couple of minutes the
> connection gets killed with the messages "NO CARRIER". When I try to do
> a reconnect, the message again is "NO CARRIER" and the kernel logs:
> isdn: hfc_usb0,ch0 cause: E0010
> 
> Again, after the connection broke down, the only thing left to me seems
> to again reboot the system.
> 
> So I wonder what could be the problem:
> - installation/configuration of HiSax/etc.?
> - hardware issue with the HFC USB ISDN-card? There are some messages of
> the hfc_usb-kernelmodule:
> HFC-S USB: driver module revision 2.3.2.24 date 2007/10/14 loaded,
> (debug=0)
> HFC-S USB: probing interface(0) actalt(0) minor(-1)
> hfc_usb: probe of 2-2.1:1.0 failed with error -5
> HFC-S USB: probing interface(1) actalt(0) minor(-1)
> HFC-S USB: detected "Billion tiny USB ISDN TA 128"
> - issue caused by the virtualization?
>

Most likely.
1.) Looks like windows do not allow the VM access to the USB
configuration of the device, so it cannot select the supported USB
configuration.
2.) Even if this issue is solved, the USB ISDN card need to fill the USB
buffers very quickly, and the buffers are relative small. Since in a VM
kernel the latency could be high and vary a lot it could cause problems.

Karsten