Method and system for directing device driver to service multiple sequential interrupt requests generated by I/O device connected thereto
US5530872A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 23, 1992 |
| Grant date | Jun 25, 1996 |
| Priority date | — |
| Expiry date | Dec 23, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F13/24
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A system and method is provided for detecting and correcting a lost hardware interrupt generated by an input/output device in a multiple I/O port computer environment. The lost interrupt condition is caused by the simultaneous occurrence of (i) the reading and subsequent resetting of a interrupt request status bit in an I/O port by a device driver and (ii) the setting of the interrupt request status bit by an I/O device attached to the port. Because the interrupt request status bit is reset before it can be read, the device driver fails to see an acknowledgement of the previous data transmission to the I/O device, and the system encounters a deadlock condition. After a normal timeout timer expires the device driver terminates transmission of data and returns a "cancel or retry" message to the request originator. The present invention prevents a deadlock condition in this situation by providing a second timer in addition to and of significantly less duration than the normal timeout timer. Upon expiration of this additional timer, the device driver, upon satisfying a number of conditions, presumes that an interrupt has been lost, and proceeds to send the next byte of data to the I/O …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.