Re: [RFC] coldplug - emit hotplug events from sysfs

[Olivier Blin <oblin@mandriva.com>]

Kay Sievers <kay.sievers@vrfy.org> writes:

>> It looks really nice, but will we still be able to differientate
>> coldplug events in udev rules?
>> For example, in Mandriva, we do PCI coldplug for USB controllers only,
>> because we handle other stuff (sound, network, ...) later in
>> services. We used to rely on UDEV_START in udev rules.
>
> Not with this simple patch. It would be possible by adding an additional
> parameter to kobject_hotplug() to add an aditional key. Or we could use a
> different ACTION value and map it with udev...
>
> But unlike udevstart/udevsynthesize, you have complete control which
> events are generated, cause you will do it from a shell script and not
> with a binary. Wouldn't it work, to just trigger the events for the
> usb controllers and and leave the others alone?

Actually, we also need to know the class of the pci device, that's why
it was handy to use an udev rule.
But of course, we could use something like that:
for i in /sys/bus/pci/devices/*; do egrep -q '0x0c03[012]0' $i/class && echo 1 > $i/uevent; done

> To play with it, I use this stupid hack in an early init-script and
> it works without udevstart or any other coldplug logic.
> After mounting tmpfs, creating /dev/null, disabling /sbin/hotplug and
> starting udevd, it creates the tty devices, waits for the events to
> finish, then sends out all remaining events to finish asynchronously:

Thanks for the explanation

> Anyway, it works on two of my boxes and is the fastest udev/coldplug
> bootup, I've ever seen. :)

Strange it's that better, udevstart/synthetize only browsed the
sysfs directories and added some environment variables.
Browsing with bash should be almost as slow.

-- 
Olivier Blin
Mandriva



-------------------------------------------------------
This SF.Net email is sponsored by:
Power Architecture Resource Center: Free content, downloads, discussions,
and more. http://solutions.newsforge.com/ibmarch.tmpl
_______________________________________________
Linux-hotplug-devel mailing list  http://linux-hotplug.sourceforge.net
Linux-hotplug-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel