Messages in this thread | | | Subject | Re: My $0.02 on devd and devfs | From | Benny Amorsen <> | Date | 12 Oct 1999 22:40:24 +0200 |
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>>>>> "dp" == david parsons <orc@pell.portland.or.us> writes:
dp> In article dp> <linux.kernel.199910120618.DAA04453@sleipnir.valparaiso.cl>, Horst dp> von Brand <vonbrand@sleipnir.valparaiso.cl> wrote:
HvB>> Nope. devd is notified when the device shows up.
dp> How?
dp> If /dev/printer/0 will be a PC-style parallel port, and I've dp> built the driver as a module, the device has shown up when the dp> machine is built, but the driver is sitting there waiting for kmod dp> to drag it into core.
Modern busses can tell which hardware is currently connected without speculatively loading drivers. PCMCIA, USB, and PCI are examples. I thought that modern devices connecting to the parallel port supported that too, but I might be wrong of course.
dp> If the file /dev/printer/0 doesn't exist, I can't open it and dp> can't tell kmod to load the driver.
It could be created at device detection time -- that is right after the device is connected.
dp> So what I need to do is either discard modules altogether or dp> do a speculative load of every driver module in the system at dp> bootup so that I can generate the appropriate detect messages for dp> devd to populate /dev. If I have to jump through all of these dp> hoops, what do I gain over just populating /dev with every dp> possible device?
You just populate it with the devices from /proc/bus/*.
Benny
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