On Fri, Aug 7, 2009 at 18:10, Nigel Kukard<nkukard@xxxxxxxx> wrote: > I think you guys are missing the problem I'm having. This has nothing to > do with USB, I don't use USB and don't load any USB modules. I've tried > this out on 3 boxes using kernel 2.9.29.6 and udev 145. > > Here are the modules loaded ... > ahci, piix, ide_core, ata_piix, pata_acpi, libata > > * I have a kernel with an initramfs, no disk controller modules are > loaded at all before the initramfs fires up > * My script is this .... > examine pci bus & modprobe modules we need for disks > fire up udev > udev trigger > udev settle > mount LABEL=root > > Simple. Now .... that works in 141 fine, it does not in 145. If I do an > ls /dev straight after settle, there are no sd* devices. If I add a > sleep 5s after settle, the devices are there. > > udevadm settle exits after about 1 second, when I check the creation > times on the devices it takes a few seconds, up to 5 depending on the > speed of the box. > > Kay, you said yourself that settle does not wait until the events are > fully processed and exits once they have been recieved by udev. I did? Where? Must be misunderstanding. > This is > EXACTLY what is happening in 145. settle waits for all pending events in the kernel, and the ones already received by udev, to finish. It exits not before no events are pending anymore, in the kernel and in udev. > You further said this is due to the > speed improvements with 145 and I was just lucky in 141 and I should be > waiting for the udev event that the device has been processed. I went > over the chat logs again to make sure I'm not imagining things. Not sure what you mean, but it's probably not pending events and udevsettle which causes your problem. Sound like events which are not pending. You definitely can not be sure that there are no future events coming in, which are not queued anywhere at this moment, not in the kernel, not in udev. You can not be sure about this at any point. And settle can not do anything here. It's just the next interrupt from the hardware that may cause your device to appear, and there is usually no way to predict that. > This will not work ... udevadm settle > --exit-if-exists=/dev/disk/by-label/foo , 'udevadm settle' exits > BEFORE the device is created. Might be. But then no event is pending as described above. If you wait for a specific device, just loop until it shows up. I guess, you just cannot use the udev queue to tell you anything it does not know. Kay -- To unsubscribe from this list: send the line "unsubscribe linux-hotplug" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
