Re: [hylafax-users] Kernel 2.6.26 Apparently Breaks USB Fax Modem

[Frank Peters <frank.peters@xxxxxxxxxxx>]

On Fri, 22 Aug 2008 11:44:20 -0400
Aidan Van Dyk <aidan@xxxxxxxx> wrote:

>  
> > That patch seems to solve the buffer problem, but now,
> > according to the HylaFAX logs, the fax transmission
> > fails for a different reason.  The data transfer now
> > seems abnormally fast.  The page may be transferred
> > and things may stall with the post-page negotiation.
> 
> That sounds like it might be broken flowcontrol..  You might try
> switching to doing software flow-control directly with the modem instead
> of relying on hardware flow-control...
> 

Flow control is determined by the setting in the configuration
file.  If that's correct, I changed the ModemFlowControl
from "rtscts" to "xonxoff" in the configuration and then sent
a fax as usual.  According to the HylaFAX logs, the transmission
failed in exactly the same way as before the change.

Since I can't really decipher the logs I can only try to make
reasonable guesses about what is happening, and I am not exactly
sure just what is going on at the point of failure.

But HylaFAX is irrelevant.  The problem is within the cdc-acm
kernel module which controls communication with a USB modem.
For anyone interested, I've posted both kernel debugging logs
and HylaFAX logs to the linux-usb mailing list, but I
don't know if file attachments actually make it to the archives.

Frank Peters


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