Messages in this thread | | | Date | Thu, 14 Oct 1999 10:46:47 -0700 (PDT) | From | David Lang <> | Subject | Re: My $0.02 on devd and devfs |
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On Thu, 14 Oct 1999, Horst von Brand wrote:
> orc@pell.portland.or.us (david parsons) said: > > In article <linux.kernel.199910141142.IAA10452@pincoya.inf.utfsm.cl>, > > Horst von Brand <vonbrand@inf.utfsm.cl> wrote: > > >orc@pell.portland.or.us (david parsons) said: > > > >[...] > > > >> I think there may be a bit of confusion here. The PC-style ports > > >> already exist, and Linux already handles them. If I build a modular > > >> kernel (which I do), the current version of Linux will already do the > > >> fbm needed to load the drivers and give me access. If I use a > > >> devfs, current 2.3.x's will do the fbm needed to load the drivers and > > >> give me access without any changes to userland. But if I use devd as > > >> described in recent email on the kernel list, I either have to have > > >> the device nodes already installed or I have to bloat my kernel with > > >> the detection parts of the drivers or I have to build the drivers > > >> into the kernel. > > > >The described kernel will notify devd to create the nodes when they show > > >up, i.e., on boot or when the device is plugged in. > > > How? > > > > Until I insmod the parallel port driver, the kernel doesn't know > > that there are any parallel ports around. > > Because it doesn't check before. > > > >Any dynamic /dev will > > >have to include this exact functionality somehow, > > > Perhaps it would be a good idea if you wasted the five minutes > > necessary to look at Richard Gooch's code before you commented > > further on it. > > Look, to find out if the foo device is present, you _have_ to check > somehow. No way around that. I somehow seriously doubt devfs does some > mindreading trick here.
Actually, in a way it does. It can be setup so that if you attempt to access a parallel port device it then goes and insmods the driver. this allows it to not do a scan of everything to start.
David Lang
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