VJ compression error using ppp

Howdy,

I've got two distro's of AMD64, both with kernels 2.4.2x and both with
the same modem problem. when connecting, the systems (Mandrake and
Suse) both run /sbin/ifup ppp0, which dials out and connects ok. In
Mandrake it returned an error "can't find bsd_compress", which I fixed
by enabling bsd_compress in menuconfig and recompiling. But now both
kernels have the same problem - they report "VJ compression error" and
no data gets to the screen from the modem.

Since I have an external modem with led's, I can see that data is
received when the led's flash. But nothing ever shows up on the screen.

The modem works fine on a 32 bit box using 2.2.22 kernel.

Any suggestions on how to get the AMD64 running the same way that the
old 32 bit box did appreciated!

Patience, persistence, truth,
Dr. mike

Mike Rosing <mrosing@wisc.edu> wrote:

> I've got two distro's of AMD64, both with kernels 2.4.2x and both with
> the same modem problem. when connecting, the systems (Mandrake and

It's not a modem problem. Modems don't know about VJ compression.

> Suse) both run /sbin/ifup ppp0, which dials out and connects ok. In
> Mandrake it returned an error "can't find bsd_compress", which I fixed
> by enabling bsd_compress in menuconfig and recompiling. But now both
> kernels have the same problem - they report "VJ compression error" and
> no data gets to the screen from the modem.

Are you sure it's not a VJ *decompression* error that's reported?

> Since I have an external modem with led's, I can see that data is
> received when the led's flash. But nothing ever shows up on the screen.

> The modem works fine on a 32 bit box using 2.2.22 kernel.

Weel, if nothing ever shows up for received traffic except flashing
LEDs and the kernel truly says "VJ compression error" then it's not
caused by what I thought it might be. The thing I had in mind was
a bug in the remote's VJ compression and would show up on a 32-bit
box as well.

> Any suggestions on how to get the AMD64 running the same way that
> the old 32 bit box did appreciated!

You can try asking the Linux PPP maintainer, Paul Mackerras, if
this could be a bug in the kernel PPP code for a 64-bit kernel.
You can also ask on the Linux PPP mailing list by sending an email
to linux-ppp@vger.kernel.org. Paul's email address can be found in
the README.linux file of the pppd source.

--
Clifford Kite Email: "echo xvgr_yvahk-ccc@ri1.arg|rot13"
PPP-Q&A links, downloads: http://ckite.no-ip.net/

Clifford Kite wrote:
> Mike Rosing <mrosing@wisc.edu> wrote:
>
>
>>I've got two distro's of AMD64, both with kernels 2.4.2x and both with
>>the same modem problem. when connecting, the systems (Mandrake and
>
>
> It's not a modem problem. Modems don't know about VJ compression.
>
>
>>Suse) both run /sbin/ifup ppp0, which dials out and connects ok. In
>>Mandrake it returned an error "can't find bsd_compress", which I fixed
>>by enabling bsd_compress in menuconfig and recompiling. But now both
>>kernels have the same problem - they report "VJ compression error" and
>>no data gets to the screen from the modem.
>
>
> Are you sure it's not a VJ *decompression* error that's reported?
>
>
>>Since I have an external modem with led's, I can see that data is
>>received when the led's flash. But nothing ever shows up on the screen.
>
>
>>The modem works fine on a 32 bit box using 2.2.22 kernel.
>
>
> Weel, if nothing ever shows up for received traffic except flashing
> LEDs and the kernel truly says "VJ compression error" then it's not
> caused by what I thought it might be. The thing I had in mind was
> a bug in the remote's VJ compression and would show up on a 32-bit
> box as well.
>
>
>>Any suggestions on how to get the AMD64 running the same way that
>>the old 32 bit box did appreciated!
>
>
> You can try asking the Linux PPP maintainer, Paul Mackerras, if
> this could be a bug in the kernel PPP code for a 64-bit kernel.
> You can also ask on the Linux PPP mailing list by sending an email
> to linux-ppp@vger.kernel.org. Paul's email address can be found in
> the README.linux file of the pppd source.
>
Thanks. I found a few hints from the HOWTO and several other messages
in the PPP code and headers. By adding the line "novj" to the file
/etc/ppp/options the problem was cured. Most of the hints were from
"turn on vj compression for ISDN". Since I don't have ISDN, it seemed
safe to turn it off instead!

But now my system doesn't boot any more, so I'm back to square one.
I think re-installing and starting over from scratch, then putting this
edit in is my best chance!

Patience, persistence, truth,
Dr. mike

Mike Rosing <mrosing@wisc.edu> wrote:
>> You can try asking the Linux PPP maintainer, Paul Mackerras, if
>> this could be a bug in the kernel PPP code for a 64-bit kernel.
>> You can also ask on the Linux PPP mailing list by sending an email
>> to linux-ppp@vger.kernel.org. Paul's email address can be found in
>> the README.linux file of the pppd source.

> Thanks. I found a few hints from the HOWTO and several other messages
> in the PPP code and headers. By adding the line "novj" to the file
> /etc/ppp/options the problem was cured. Most of the hints were from
> "turn on vj compression for ISDN". Since I don't have ISDN, it seemed
> safe to turn it off instead!

If the error message concerned decompression rather than compression
then the novjccomp option should eliminate it and you'll retain most of
the benefits of VJ compression.

-- Clifford Kite Email: "echo xvgr_yvahk-ccc@ri1.arg|rot13"
/* Recipe for a unified PPP debug log file: Add the line
daemon.*;local2.* /var/log/ppp.log
to /etc/syslog.conf, and do " killall -HUP syslogd " so that
so that syslogd rereads it. And add the pppd debug option. */