-----Original Message----- From: Erik Mouw [mailto:mouw@xxxxxxxxxxxx] Sent: Tuesday, July 17, 2007 5:37 PM To: Rajendra Stalekar Cc: kernelnewbies@xxxxxxxxxxxx Subject: Re: Doubt on Interrupt sharing -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Tue, Jul 17, 2007 at 05:26:44PM +0530, Rajendra Stalekar wrote: > 1. Why is it not correct to install the interrupt handler during driver > initialization and it's better to install it when we are actually opening > the device. Because you would be servicing interrupts for an unused device. That wastes: - - CPU time - - Memory resources - - Energy (important for laptop users) Rajendra :- When we are not using the device itself(i.e. not opened the device) , what kind of interrupts can we get for that device? > 2. How can we share the same interrupt line if we install for 2 or more > devices, when that interrupt is allocated to a particular device ? A single interrupt line can be assigned to more than one device. Rajendra :- How can that be done? Is it not a physical interrupt line(wire), how can that line go to multiple devices. > I can understand during driver initialization it's not a good idea to > install the handler because we don't know whether we are going to use the > device. > > But if we install the handler when the device is opened how can we share the > interrupt line because it is now dedicated for it. An dedicated interrupt line for a single device is very uncommon these days. It used to be normal for ISA, but ISA is dead. Erik - -- They're all fools. Don't worry. Darwin may be slow, but he'll eventually get them. -- Matthew Lammers in alt.sysadmin.recovery -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFGnLDy/PlVHJtIto0RApY/AJoDfiz8ApSVTWs5e758laKikqomDACfUY8k YRnZSiz0e6DZhCchTX/FD+I= =Dvwk -----END PGP SIGNATURE----- -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
