We have several CentOS 6 systems that are used in various configurations of test equipment. One of the primary functions of these systems is the connectivity to serial ports of some operational systems that have serial port control requirements. Lack of interface bus slots led us to the use of USB connected serial ports on these CentOS 6 systems.
We first used these USB connected serial ports in our RHEL 5 test equipment systems. With RHEL 5, shut down and boot up of the systems would often cause the serial ports to have a different driver name, even though we had not changed the ports where the USB devices were plugged in. This caused software access problems until we discovered what could be done using the udev rules to lock in the driver names.
This problem seems to have gone away in our newer systems with CentOS 6, and we would like to make sure that it does not return. We are deploying some of the systems and do not want to have software access issues in the field where fixes are more difficult. We would like to know if there is some underlying factor that has solved this problem for us. Any ideas on what to check would be greatly appreciated.
-----Original Message----- From: Chris Olson [mailto:chris_e_olson@yahoo.com] Sent: Thursday, November 16, 2017 5:42 PM To: CentOS Mailing List Subject: [CentOS] USB Serial Ports
We have several CentOS 6 systems that are used in various configurations of test equipment. One of the primary functions of these systems is the connectivity to serial ports of some operational systems that have serial port control requirements. Lack of interface bus slots led us to the use of USB connected serial ports on these CentOS 6 systems.
We first used these USB connected serial ports in our RHEL 5 test equipment systems. With RHEL 5, shut down and boot up of the systems would often cause the serial ports to have a different driver name, even though we had not changed the ports where the USB devices were plugged in. This caused software access problems until we discovered what could be done using the udev rules to lock in the driver names.
This problem seems to have gone away in our newer systems with CentOS 6, and we would like to make sure that it does not return. We are deploying some of the systems and do not want to have software access issues in the field where fixes are more difficult. We would like to know if there is some underlying factor that has solved this problem for us. Any ideas on what to check would be greatly appreciated.
I have no idea why it is working better under 6, but it is possible to use UDEV rules to force them to be at expected /dev/my_tty* locations using vendor_ID/device_ID/serial_number combinations. Once you figure that out, you should even be able to use the same (or at least similar) rules under 7.
-- Even when this disclaimer is not here: I am not a contracting officer. I do not have authority to make or modify the terms of any contract.
On 11/17/2017 10:06 AM, Denniston, Todd A CIV NAVSURFWARCENDIV Crane, JXVS wrote:
-----Original Message----- From: Chris Olson [mailto:chris_e_olson@yahoo.com] Sent: Thursday, November 16, 2017 5:42 PM To: CentOS Mailing List Subject: [CentOS] USB Serial Ports
We have several CentOS 6 systems that are used in various configurations of test equipment. One of the primary functions of these systems is the connectivity to serial ports of some operational systems that have serial port control requirements. Lack of interface bus slots led us to the use of USB connected serial ports on these CentOS 6 systems.
We first used these USB connected serial ports in our RHEL 5 test equipment systems. With RHEL 5, shut down and boot up of the systems would often cause the serial ports to have a different driver name, even though we had not changed the ports where the USB devices were plugged in. This caused software access problems until we discovered what could be done using the udev rules to lock in the driver names.
This problem seems to have gone away in our newer systems with CentOS 6, and we would like to make sure that it does not return. We are deploying some of the systems and do not want to have software access issues in the field where fixes are more difficult. We would like to know if there is some underlying factor that has solved this problem for us. Any ideas on what to check would be greatly appreciated.
I have no idea why it is working better under 6, but it is possible to use UDEV rules to force them to be at expected /dev/my_tty* locations using vendor_ID/device_ID/serial_number combinations. Once you figure that out, you should even be able to use the same (or at least similar) rules under 7.
I have been using udev rules for usb serial ports for a few years now. First on CentOS 6.? , IIRC, now on 7.4, and simultaneously on several Fedora releases, currently F26. I would be glad to send the file that I put in /etc/udev/rules.d/ if that would help in any way
-- Even when this disclaimer is not here: I am not a contracting officer. I do not have authority to make or modify the terms of any contract.
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Chris Olson -
Denniston, Todd A CIV NAVSURFWARCENDIV Crane, JXVS -
Wells, Roger K.