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Method for suspending and then continuing a shared serial port driver and application

IP.com Disclosure Number: IPCOM000016548D
Original Publication Date: 2003-Jun-27
Included in the Prior Art Database: 2003-Jun-27
Document File: 1 page(s) / 37K

Publishing Venue

IBM

Abstract

Method for suspending and then continuing a shared serial port driver and application.

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This is the abbreviated version, containing approximately 68% of the total text.

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  Method for suspending and then continuing a shared serial port driver and application

    A Netfinity server product has an intelligent PCI card (sometimes called a support processor) plugged into a PCI slot of a host system. This PCI card has a serial port on it. This serial port was to be shared between the operating system (OS) on the PCI card and the host operating system. When the OS on the PCI card wanted to use the serial port it would cause a modem status interrupt to the device driver on the host. Normally this interrupt would be reported back to the using application , possibly in the middle of data transfer, and the application would be terminiated.

Our invention is to modify the host's shared serial port's device driver modem status interrupt handler. If a flag is on indicating the PCI card took the serial port, then the interrupt would not be reported to the application. Rather, a finite timer with a callback would be started and return to the host OS but the modem status interrupt would not be posted. When the timer expired and the callback point is engaged, the flag is checked. If the flag still indicates the PCI card still owns the serial port, then the finite timer/callback would be restarted. If the flag indicates the PCI card does not own the serial port anymore, then operation would continue on as normal. This is assuming the host's application did not have any timeout period from not communicating with the serial port and it would not stop itself...