Alan McKinnon wrote: > As I see it, at the bottom of the stack you have a kernel and at the top a > user space app (the X server will do for an example). Plug in a USB device > that the app can use, and the kernel needs to make a node in /dev for it if > it's not already there. The kernel should not be interrogating the device for > all possible info - that is expensive - and doesn't need to. It only needs > enough info to know what driver, major and minor numbers to use. X OTOH, can
I couldn't agree more. And this is what Udev, as a user space app, does. The only thing it doesn't handle is communicating with other user space apps; this is currently Hals job. > the current model uses udev as the interface to the kernel's nodes and HAL as > the interface to exactly what hardware you have. Seems pretty sane for the > most usual use case. At some point in the stack you will need the > OS-dependant > part, my guess is the best place is between hal and udev. Only Linux uses Well, as I understand it this is what it looks like today: kernel <-> udev (or equivalent for non-linux kernel/OS) <-> hal <-> dbus <-> user apps To me that seems a bit redundant... What I would like to see: kernel <-> udev <-> user apps Or at the most: kernel <-> udev <-> daemon <-> user apps. > udev, but all OSes use something in that spot. And if not, they have static > nodes. Yes, but if the developers could agree on a common API for the udev daemon and it's equivalents on other platforms (what does BSD use?)... Or if they could agree on using "Hal v2" (rewritten from scratch with no or a minimum of dependencies). > Meanwhile we have an acknowledged problem with hal - it's too complex, too > many things have been shoved into it that were never catered for in the > design, configuration is horrific - and the devs are having their usual > spirited debate about how best to approach a solution. This is perfectly > normal and perfectly healthy Yes, I guess so. Since I'm (currently) not in the position to help out I'll have to live with whatever they come up with. But sometimes it's a bit frustrating... Sorry for the ranting. Best regards Peter K
