Compaq AA-RNG2A-TE manual Enabling the Interrupt Handler, Starting the Polling Process

6.11 Enabling the Interrupt Handler

The following code shows how the el_attach( ) routine enables the interrupt handler:

handler_enable(sc->hid);

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Calls the handler_enable( ) routine to enable a previously registered interrupt handler. The el_probe( ) routine calls handler_add to register the interrupt handler and it stores the handler ID in the hid member of the el_softc data structure for this device.

6.12 Starting the Polling Process

The following code shows how the el_attach( ) routine starts the polling process:

if (el_polling && !sc->polling_flag) { 1 sc->polling_flag = 1;

timeout((void *)el_intr, (void *)unit, (1*hz)/el_pollint);

}else sc->polling_flag = 0; 2

return(0);

}

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Starts the polling process if the el_polling attribute specifies that polling is to be done.

To start the polling process, el_attach( ) sets the polling_flag member to 1 (true), then calls the timeout( ) routine to schedule the interrupt handler to run at some point in the future. timeout( ) is called with the following arguments:

•A pointer to the el_intr( ) routine, which is the if_el device driver’s interrupt handler.

•The unit variable, which contains the controller number associated with this device. This argument is passed to the el_intr( ) routine.

•The el_pollint variable, which specifies the amount of time to delay before calling the el_intr( ) routine.

If the user requests that polling be disabled, el_attach( ) sets the polling_flag member to 0 (false).

6–10Implementing the Autoconfiguration Support Section (attach)