On Fri, Jul 20, 2007 at 03:27:32PM +0530, Rajendra Stalekar wrote: > > -----Original Message----- > From: Greg KH [mailto:greg@xxxxxxxxx] > Sent: Friday, July 20, 2007 1:42 PM > To: Rajendra Stalekar > Cc: kernelnewbies@xxxxxxxxxxxx > Subject: Re: doubts on device probing(auto-detection) > > On Fri, Jul 20, 2007 at 11:42:19AM +0530, Rajendra Stalekar wrote: > > Hi, > > > > 1. When we probe a device, how does it find out that the device actually > > exists and is functional? > > What type of device? ISA? PCI? USB? Firewire? Something else? > > They all work differently depending on the bus type. > > Rajendra:- PCI would be a good example I suppose. Note that they all work differently, so it does matter. > > 2. Do we probe for interrupts to check which interrupt line(s) can be > > assigned to the device in question? > > USB devices don't have interrupts, so you are going to have to be more > specific here :) > > > 3. When the driver is calling probe_irq_on, it returns a bit mask of > > unassigned interrupts. In such case driver assigns an interrupt line for > > that specific device, Am I right? > > No modern driver should ever call that function. > > Rajendra:- Is it because the devices are intelligent enough so that they > announce the IRQ? No, it's because the driver core for that subsystem handles this already for the devices, no individual driver work is needed (in the case of PCI and USB, ISA is a different story...) thanks, greg k-h -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
