[gentoo-embedded] Automatic module loading not working?

[Ed W]

Hi, I apologise if this is a very newbie question, but - I have an Alix 
board and custom kernel which doesn't seem to be autoloading kernel modules

The Alix is running 2.6.29, uclibc 0.9.30.1, busybox 1.14.2, Udev 141, 
openrc 0.40.  When I insert any hardware, eg trying now with a USB GPS 
then I get a bunch of general USB nodes created, but the pl2303 module 
(used with this device) is not auto loaded.  If I modprobe this module 
then everything works as expected.

On my desktop machine (2.6.29, and a more standard AMD64 build, but 
still with openrc), I see udev loading my modules correctly.

Here is the log from udevadm status on the Alix:

KERNEL[946736607.038720] add      
/devices/pci0000:00/0000:00:0f.4/usb2/2-1 (usb)
UDEV  [946736607.041839] add      
/devices/pci0000:00/0000:00:0f.4/usb2/2-1 (usb)
KERNEL[946736607.042595] add      
/devices/pci0000:00/0000:00:0f.4/usb2/2-1/2-1:1.0 (usb)
KERNEL[946736607.043576] add      
/devices/pci0000:00/0000:00:0f.4/usb2/2-1/2-1:1.0/usb_endpoint/usbdev2.6_ep81 
(usb_endpoint)
KERNEL[946736607.044331] add      
/devices/pci0000:00/0000:00:0f.4/usb2/2-1/2-1:1.0/usb_endpoint/usbdev2.6_ep02 
(usb_endpoint)
KERNEL[946736607.045158] add      
/devices/pci0000:00/0000:00:0f.4/usb2/2-1/2-1:1.0/usb_endpoint/usbdev2.6_ep83 
(usb_endpoint)
KERNEL[946736607.045688] add      
/devices/pci0000:00/0000:00:0f.4/usb2/2-1/usb_device/usbdev2.6 (usb_device)
KERNEL[946736607.046425] add      
/devices/pci0000:00/0000:00:0f.4/usb2/2-1/usb_endpoint/usbdev2.6_ep00 
(usb_endpoint)
UDEV  [946736607.066290] add      
/devices/pci0000:00/0000:00:0f.4/usb2/2-1/usb_device/usbdev2.6 (usb_device)
UDEV  [946736607.081372] add      
/devices/pci0000:00/0000:00:0f.4/usb2/2-1/usb_endpoint/usbdev2.6_ep00 
(usb_endpoint)
UDEV  [946736607.101506] add      
/devices/pci0000:00/0000:00:0f.4/usb2/2-1/2-1:1.0 (usb)
UDEV  [946736607.104493] add      
/devices/pci0000:00/0000:00:0f.4/usb2/2-1/2-1:1.0/usb_endpoint/usbdev2.6_ep81 
(usb_endpoint)
UDEV  [946736607.107785] add      
/devices/pci0000:00/0000:00:0f.4/usb2/2-1/2-1:1.0/usb_endpoint/usbdev2.6_ep83 
(usb_endpoint)
UDEV  [946736607.110207] add      
/devices/pci0000:00/0000:00:0f.4/usb2/2-1/2-1:1.0/usb_endpoint/usbdev2.6_ep02 
(usb_endpoint)


And now on the desktop machine (now my pl2303 is added automatically):

KERNEL[1250157653.739660] add      
/devices/pci0000:00/0000:00:1d.0/usb6/6-2 (usb)
UDEV  [1250157653.740370] add      
/devices/pci0000:00/0000:00:1d.0/usb6/6-2 (usb)
KERNEL[1250157653.742698] add      
/devices/pci0000:00/0000:00:1d.0/usb6/6-2/6-2:1.0 (usb)
KERNEL[1250157653.742719] add      
/devices/pci0000:00/0000:00:1d.0/usb6/6-2/6-2:1.0/usb_endpoint/usbdev6.5_ep81 
(usb_endpoint)
KERNEL[1250157653.742744] add      
/devices/pci0000:00/0000:00:1d.0/usb6/6-2/6-2:1.0/usb_endpoint/usbdev6.5_ep02 
(usb_endpoint)
KERNEL[1250157653.742759] add      
/devices/pci0000:00/0000:00:1d.0/usb6/6-2/6-2:1.0/usb_endpoint/usbdev6.5_ep83 
(usb_endpoint)
KERNEL[1250157653.742775] add      
/devices/pci0000:00/0000:00:1d.0/usb6/6-2/usb_endpoint/usbdev6.5_ep00 
(usb_endpoint)
UDEV  [1250157653.743187] add      
/devices/pci0000:00/0000:00:1d.0/usb6/6-2/usb_endpoint/usbdev6.5_ep00 
(usb_endpoint)
KERNEL[1250157653.744917] add      /module/pl2303 (module)
KERNEL[1250157653.744991] add      /bus/usb-serial/drivers/pl2303 (drivers)
UDEV  [1250157653.745260] add      /module/pl2303 (module)
UDEV  [1250157653.745344] add      /bus/usb-serial/drivers/pl2303 (drivers)
KERNEL[1250157653.756463] add      
/devices/pci0000:00/0000:00:1d.0/usb6/6-2/6-2:1.0/ttyUSB0 (usb-serial)
KERNEL[1250157653.756662] add      
/devices/pci0000:00/0000:00:1d.0/usb6/6-2/6-2:1.0/ttyUSB0/tty/ttyUSB0 (tty)
KERNEL[1250157653.756714] add      /bus/usb/drivers/pl2303 (drivers)
UDEV  [1250157653.756868] add      
/devices/pci0000:00/0000:00:1d.0/usb6/6-2/6-2:1.0 (usb)
UDEV  [1250157653.757187] add      /bus/usb/drivers/pl2303 (drivers)
UDEV  [1250157653.757536] add      
/devices/pci0000:00/0000:00:1d.0/usb6/6-2/6-2:1.0/usb_endpoint/usbdev6.5_ep81 
(usb_endpoint)
UDEV  [1250157653.758064] add      
/devices/pci0000:00/0000:00:1d.0/usb6/6-2/6-2:1.0/usb_endpoint/usbdev6.5_ep02 
(usb_endpoint)
UDEV  [1250157653.758171] add      
/devices/pci0000:00/0000:00:1d.0/usb6/6-2/6-2:1.0/usb_endpoint/usbdev6.5_ep83 
(usb_endpoint)
UDEV  [1250157653.758514] add      
/devices/pci0000:00/0000:00:1d.0/usb6/6-2/6-2:1.0/ttyUSB0 (usb-serial)
UDEV  [1250157653.768152] add      
/devices/pci0000:00/0000:00:1d.0/usb6/6-2/6-2:1.0/ttyUSB0/tty/ttyUSB0 (tty)


I believe I have all the kernel options required for udev (can post 
.config if useful?), but this seems like a kernel config issue at my end?

Can anyone please give me some advice on debugging this further?  Am I 
missing something in the kernel? (CONFIG_KMOD is implicit in all recent 
kernels anyway).  Is this something I'm missing in my udev setup, or 
some problem with my busybox config (it seems to be ok modprobing module 
aliases?)

I notice that rebooting with the device connected doesn't change 
anything (but I don't think I have any coldplug options set in openrc, 
not sure if these even exist anymore?).  I have a fairly minimal set of 
packages installed on the Alix - is it possible that I am missing some 
dependency that allows udev to do it's magic?  There are no errors here, 
so I'm assuming a kernel problem rather than a udev problem?

Thanks for any help


Ed W