Reattach/redetect allways connected umass device - is it possible ?

[Vladimir Grebenschikov]

Hi 

I have SONY notebook with integrated memory stick card reader. It
appears as USB umass device and works well.

Usbdevs output is here: 
Controller /dev/usb3:
addr 1: high speed, self powered, config 1, EHCI root hub(0x0000), Intel(0x0000), rev 1.00, device uhub4
 port 1 powered
 port 2 powered
 port 3 powered
 port 4 powered
 port 5 addr 2: high speed, self powered, config 1, USB Memory Stick Slot(0x014d), Sony(0x054c), rev 1.10, device umass1
 port 6 powered

Only problem is that card-reader itself toes not detach USB device on flash removal. So if I change card to another card of different size 
it is not detected and da0 device still has old geometry.

'camcontrol rescan' does not helps.

For previous Sony notebook stick reader was attached to ATA bus and I workaround this problem with atacontrol detach/attach.

How to do same with USB-attached umass device, I mean how to rescan this device for physical geometry.

I found only solution - kldunload umass && kldload umass, but it is ugly. And can be problem in case when another umass device connected.

-- 
Vladimir B. Grebenchikov
vova at fbsd.ru