Shared I/O problem

Angelo Fraietta angelo_f at
Thu Mar 17 04:51:29 UTC 2005

willisfield wrote:

> We know tasks can be preempted in RTEMS. If one task is using an io 
> device, at the same time the task is preempted by another task which 
> will use the io device. The state of the io device will be changed and 
> when the first task restarts, how to recover the state of the io 
> device? that is to say how to resolve the situation that one io device 
> can be used between different tasks of RTEMS?
> Thanks for your reading and any answer is appreatiated!
Place a semaphore around the calls to write to the device so only one 
task is allowed to write to it an any time.

Angelo Fraietta

PO Box 859
Hamilton NSW 2303

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