It would be nice if we could switch from usb mass storage to charge only without having to disconnect the cable. Currently only the reverse is possible, charge->usb mass storage.

Is there I way, or should I start brainstorm maybe

I don't have USB cable at hand to test but what about unmounting the N900 from the PC, keeping the cable connected?

It works but N900 notification at the top is stuck at mass storage mode, even though it is unmounted. (tested on Ubuntu 9.04)

I have unmounted it in ubuntu, but I still can't access the memory card on the phone.

So is this a brainstorm or bug-report then?

Sounds like a enhancement request to me ("allow to go back to normal charging mode by using the usb status applet").

Use cases:
- Wanting access to MyDocs again without rebooting the device or the computer (or unplugging), after ejecting the device from Windows.
- Ensuring the host OS can no longer access the device as a mass storage device (paranoia ).

Not sure how relevant it is.. but under linux (ubuntu something)

umount /dev/usbstoragedevice

unmounts the file system.. but you could always mount it again

mount /dev/usbstoragedevice /mnt/usbstick

Ejecting is something different

eject /dev/usbstoragedevice
Now the device is unmounted and is no longer accessible..

eject is traditionally used with cdrom drives.. to open the tray..

eject -t closes the tray and although we're talking USB memory sticks

eject -t /dev/usbstoragedevice

is effectively the same as plugging the USB device back in..the OS detects it as a attach and will according to what does normally mount the device again..

So

ejecting the N900 from the host should effectively be the same as a USB disconnect without removing the cable.. If I had my linux machine with me, I'd give it a go..

This bug report and the discussion might be relevant here: https://bugs.maemo.org/show_bug.cgi?id=6216