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6.11 Enabling the Interrupt Handler
The following code shows how the el_attach( ) routine enables the
interrupt handler:
handler_enable(sc->hid); 1
1
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);
}
1 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.
2 If the user requests that polling be disabled, el_attach( ) sets the
polling_flag member to 0 (false).
6–10 Implementing the Autoconfiguration Support Section (attach)