I have tried booting a Dreamplug with the 3.10.10 kernel, but it fails to boot successfully, and I would appreciate some guidance as to how to work around the problem.

The symptoms are that it drops into dracut, reporting that it cannot find the root filesystem on /dev/sdb3 (another Dreamplug with slightly different config does exactly the same but with /dev/sda2).

I think the problem is that the ehci-orion driver is not being loaded.

On the Fedora kernel, I get the following messages at boot:
[   18.767308] libphy: Fixed MDIO Bus: probed
[   18.771637] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[   18.778214] ehci-pci: EHCI PCI platform driver
[   18.782734] ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
[   18.788992] uhci_hcd: USB Universal Host Controller Interface driver
[   18.795633] usbcore: registered new interface driver usbserial
[   18.801524] usbcore: registered new interface driver usbserial_generic
[   18.808129] usbserial: USB Serial support registered for generic
[   18.814399] mousedev: PS/2 mouse device common for all mice

Booting with a kernel from http://www.xilka.com/sheeva/, I get
[    6.911191] libphy: orion_mdio_bus: probed
[    6.911386] mv643xx_eth: MV-643xx 10/100/1000 ethernet driver version 1.4
[    6.912865] mv643xx_eth_port mv643xx_eth_port.0 eth0: port 0 with MAC address f0:ad:4e:00:84:db
[    6.914207] mv643xx_eth_port mv643xx_eth_port.1 eth1: port 0 with MAC address f0:ad:4e:00:84:dc
[    6.914353] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[    6.914359] ehci-pci: EHCI PCI platform driver
[    6.914506] ehci-orion: EHCI orion driver
[    6.914597] orion-ehci f1050000.ehci: EHCI Host Controller
[    6.914621] orion-ehci f1050000.ehci: new USB bus registered, assigned bus number 1
[    6.914754] orion-ehci f1050000.ehci: irq 19, io mem 0xf1050000
[    6.934742] orion-ehci f1050000.ehci: USB 2.0 started, EHCI 1.00
[    6.935444] hub 1-0:1.0: USB hub found
[    6.935463] hub 1-0:1.0: 1 port detected
[    6.936156] usbcore: registered new interface driver usb-storage
[    6.936293] usbcore: registered new interface driver ums-cypress
[    6.936436] usbcore: registered new interface driver ums-datafab
[    6.936572] usbcore: registered new interface driver ums-freecom
[    6.936708] usbcore: registered new interface driver ums-jumpshot
[    6.936844] usbcore: registered new interface driver ums-sddr09
[    6.936982] usbcore: registered new interface driver ums-sddr55
[    6.937450] mousedev: PS/2 mouse device common for all mice

and it then successfully goes on to find the SD cards and USB attached disc. (This kernel has other problems such as no console output, and leaving the root filesystem mounted read-only, so using this isn't a solution).

One difference relating to this is that the xilka kernel is built with
CONFIG_USB_EHCI_HCD_ORION=y
whereas the Fedora kernel is built with:
CONFIG_USB_EHCI_HCD_ORION=m

But I think the problem probably really lies in that there is no usr/lib/modules/3.10.10-100.fc18.armv5tel.kirkwood/kernel/drivers/usb/host/ehci_orion.ko in my uinitrd-3.10.10-100.fc18.armv5tel.kirkwood, which I assume is related to ehci_orion having been moved to device tree support.

Is my diagnosis likely to be correct, and if so, is there a simple way that I can fix it by rebuilding a uinitrd file (if so, what commands do I need to do it)? Are there likely to be any other drivers that ehci_orion.ko depends on that would also need to be included?

Finally, should a new kernel package be produced that does include the ehci_orion driver? And if so, would it be helpful if I filed a bug.

Just to confirm, the kernel is picking up the Dreamplug device tree, since I get the following message at the start of the boot sequence:
[    0.000000] Machine: Marvell Kirkwood (Flattened Device Tree), model: Globalscale Technologies Dreamplug

Many thanks,
Quentin