Introduction

Supported Linux Kernels

• 2.4-based kernels on Intel and Alpha platforms
• 2.2-based kernels on Intel and Alpha platforms
• 2.0-based kernels equal or newer than 2.0.36 on Intel platforms

The driver package has been tested with the following unmodified Linux distributions:

• RedHat 7.3
• RedHat 7.2
• RedHat 7.1
• RedHat 7.0
• RedHat 6.2
• SuSe 8.0
• SuSe 7.1
• SuSe 7.0
• SuSe 6.4
• Mandrake 8.2
• Mandrake 8.0
• Mandrake 7.2
• Caldera OpenLinux 3.1.1 server
• Caldera OpenLinux 3.1.1 workstation
• Caldera OpenLinux 3.1 server
• Conectiva 6.0
• TurboLinux 7.0 workstation
• TurboLinux 6.1 workstation
• TurboLinux 6.0 server

Supported Products

• Digi One RealPort Device Server
• EtherLite 2
• EtherLite 8
• EtherLite 16
• EtherLite 32
• EtherLite 80
• EtherLite 160
• EtherLite 162
• PortServer 8
• PortServer 16
• PortServer II 16
• PortServer TS 2
• PortServer TS 4
• PortServer TS 8
• PortServer TS 16

Enhancements

• Added Transparent print support. Please read the man page for "dgrp", under section "Transparent Print" for more information.
• Changed package install to run a "configure" script first before trying to compile the driver. The script should catch most of the problems that the compile might have beforehand, and give a much better description of the problem than a cryptic compiler error message.
• Added Support for Redhat 7.3, Suse 8.0, Mandrake 8.2, and Caldera OpenLinux 3.1.1 (server and workstation)

Bug Fixes

• Fixed off-by-one error in the tbuf parsing. This bug, although very rare, could have caused the kernel to panic, or cause random kernel memory corruption.

Known Limitations

Printers

Ditty

Configuration and Startup

The software package includes two startup scripts in either the /etc/rc.d/init.d or /etc/init.d directories named "dgrp_daemon" and "dgrp_ditty". These scripts will be executed at startup automatically if the "chkconfig" tool is present on the system during the post installation phase of the driver install. Otherwise, these scripts must be manually added to the system startup.

RedHat 7.1 -- Kernel Compatibility Issues

Some 2.4 kernel-based distributions (RedHat 7.1 included) have a patch applied to them which modifies the behavior of Linux when an open of a serial port is canceled (for instance, if an application is waiting for the carrier signal and a user hits CTRL-C to kill the application).

With this behavior change, the device driver is unable to cleanup its internal data structures and the sane functioning of the driver is compromised. The classic symptom of this problem is that the command "lsmod", which (among other things) will return a count of the applications using the device driver, will return a non-zero value even if all applications associated with the serial ports are killed.

Unfortunately, it is impossible (from within the device driver) to determine which behavior is implemented in the running kernel. However, Digi now provides a workaround to allow customers with this problem to change the Digi behavior to be compatible with these "patched" kernels.

To enable the change which provides alternate behavior when a serial "open" call fails, execute the following after the device driver is loaded:

echo "alt_fail_open=1" > /proc/dgrp/info

To return to the standard behavior, execute:

echo "alt_fail_open=0" > /proc/dgrp/info

To examine the current state of this driver tuning variable:

cat /proc/dgrp/info

Unfortunately, this command must be executed each time the device driver is loaded (i.e. when the system is booted). To make this process easier for customers, the Digi standard driver startup tools will execute the command on the customer's behalf when it loads the driver if the following command is executed:

touch /usr/bin/dgrp/config/alt_fail_open