Re-entering USB drive mode?

[Rod Whiteley]

After stopping USB drive mode is there any way to restart it other than physically unplugging the cable and plugging it back in?

[knc1]

Originally Posted by Rod Whiteley

After stopping USB drive mode is there any way to restart it other than physically unplugging the cable and plugging it back in?

From which end of the cable did you "stop" it?

In other words: What have you done?
What OS is the machine running that it is plugged into?

[ixtab]

Originally Posted by knc1

From which end of the cable did you "stop" it?

In other words: What have you done?
What OS is the machine running that it is plugged into?

I don't think that really matters.

To re-phrase the OP's question differently (if I understood it correctly): After the drive was ejected from the computer, but the cable is still plugged in, is there a way to (programmatically) set the Kindle to USB drive mode again?

I am not aware of any solution.

However, the same question would be interesting for USB Network: after turning on USB network, you also have to unplug and replug the cable for the device to be recognized as a "new one". Maybe there is some software solution to "reset" the USB port which would act as if the cable was unplugged/replugged? This certainly must be possible, but I'm completely lost when it comes to electronics and circuitery, so I probably can't be of any help.

[knc1]

Originally Posted by ixtab

I don't think that really matters.

It might. There are two machines involved, both responding to "hot plug" events.

Let's walk this through in a bit of detail.

Originally Posted by ixtab

To re-phrase the OP's question differently (if I understood it correctly): After the drive was ejected from the computer, but the cable is still plugged in, is there a way to (programmatically) set the Kindle to USB drive mode again?

"Drive ejected from the computer" - that is done on the "host end" computer. You have just told the "host" that the USB drive should be disconnected (from the OS).

? Does the Kindle detect that ? (I don't have a working kindle at the moment to test this).

If the Kindle did not detect that - then nothing has changed at the Kindle "device end" of the connection. And there is nothing to be done at/on the Kindle.
What you need is to "reattach" the USB device on the host end after the "eject" on the host end.
How that gets done depends on the OS the host end is running.

If the Kindle did detect that ("eject" or "safely remove") - then you would have to "reattach" the USB device in both the Kindle/Linux OS and in the host/whatever OS.

Need more details than where provided to answer either case above.

Originally Posted by ixtab

I am not aware of any solution.

However, the same question would be interesting for USB Network: after turning on USB network, you also have to unplug and replug the cable for the device to be recognized as a "new one". Maybe there is some software solution to "reset" the USB port which would act as if the cable was unplugged/replugged? This certainly must be possible, but I'm completely lost when it comes to electronics and circuitery, so I probably can't be of any help.

We know what OS is being run at the "device end" - still would need to know what OS is being run at the "host end".
The how-to fake a "hot plug" (or "plug&play") event differs by OS.

I hope that helps clarify the reasons for my question.

[ixtab]

Originally Posted by knc1

"Drive ejected from the computer" - that is done on the "host end" computer. You have just told the "host" that the USB drive should be disconnected (from the OS).

? Does the Kindle detect that ? (I don't have a working kindle at the moment to test this).

Yep, it does. While mounted, it shows the "If you want to read while charging, eject the Kindle, but leave the cable plugged" (or so). After unmounting, it becomes usable (and also, only then do the files on /mnt/us become accessible to programs running on the Kindle, as stated in another thread).

[Rod Whiteley]

Originally Posted by ixtab

To re-phrase the OP's question differently (if I understood it correctly)...

Yes, you understood my question correctly. I notice that when my computer goes to stand-by while connected, my Kindle appears to do the same, and when my computer wakes up Kindle goes back to USB drive mode. That made me think there might be a way to fool the system. You are right, one way would be to make a special cable or USB hub with a switch to interrupt the connection for a moment.

[drauger]

Originally Posted by ixtab

Maybe there is some software solution to "reset" the USB port which would act as if the cable was unplugged/replugged?

USB Safely Remove for Windows can return back a device just stopped.

[Rod Whiteley]

Originally Posted by drauger

USB Safely Remove for Windows can return back a device just stopped.

It can? After I stop a device it disappears from the list.

[knc1]

Originally Posted by ixtab

Yep, it does. While mounted, it shows the "If you want to read while charging, eject the Kindle, but leave the cable plugged" (or so). After unmounting, it becomes usable (and also, only then do the files on /mnt/us become accessible to programs running on the Kindle, as stated in another thread).

Thank you.
I couldn't check that myself and I had forgotten that it switched to "charging" mode.

So the process would be to reverse (on the Kindle) the switch to "charging" mode;
Re-enable the "device gadget" kernel module (if it was removed by the switch);
and then - if those changes where not auto-detected by the host end OS - do a "re-attach" at the host end.

At which point, the answer to the O.P's question is: No.

If the host end OS does auto-detect the mode-change at the device (Kindle) end, then the process above should do the job.
In which case the answer to the O.P's question is: Yes.

All too complicated for me - I would rather just unplug/plug the cable.

[hostar]

-- DELETED --

[drauger]

Originally Posted by Rod Whiteley

It can? After I stop a device it disappears from the list.

I suppose it depends on your setup. After stopping USB device via USBSafelyRemove you should see it in the list as "stopped" and can just click it to return back in the system.

[geekmaster]

Originally Posted by Rod Whiteley

... I notice that when my computer goes to stand-by while connected, my Kindle appears to do the same, and when my computer wakes up Kindle goes back to USB drive mode...

Your host PC is probably powering down the USB port, as part of its "Green" energy-saving features. You should be able to disable that in your BIOS and/or in your Windows control panel. Your kindle cannot charge from a USB port that is NOT supplying power.

How to reset the USB device(s) from (host PC) software to force redetect:
http://stackoverflow.com/questions/9...he-windows-api

You can do this by ejecting the device through the CfgMgr API. For example, to go over all USB hubs and eject all devices:

Find all devices having device interface GUID_DEVINTERFACE_USB_HUB with SetupDiGetClassDevs(... DIGCF_DEVICEINTERFACE).
Enumerate over the returned device information set (SetupDiEnumDeviceInfo).
For each device, get the DevInst member:
Invoke CM_Get_Child(DevInst) and then CM_Get_Sibling repeatedly to go over all child nodes of the hub (i.e. the USB devices).
For each child node, call CM_Request_Device_Eject.

[eureka]

Following commands executed on KT did the trick:

lipc-send-event com.lab126.hal usbPlugIn
lipc-send-event com.lab126.hal usbConfigured

Disclamer: I've tried it on KT 5.1.0 after connecting it to computer with Linux and then "ejecting" KT at computer side (not physically ejecting, but rather programmatically).

[eureka]

BTW, for geeks: KT uses g_file_storage module (with parameter 'removable=y') for exporting it's "disk" as USB Mass Storage device. I've found some descriptions of it's work. As expected, this command exports diagnostic partition :

echo /dev/mmcblk0p2 > /sys/devices/platform/fsl-usb2-udc/gadget/gadget-lun0/file

Command was issued after connecting KT to computer and programmatic ejecting of KT device from computer (USB plug was still in place).

I believe, it's safe to mount exported diagnostic partition on computer for read/write. It's also could be safe to mount exported main partition on computer for read-only. Partition with /var/local should not be exported via this way (as it's mounted by KT OS in read/write mode). The same applies for userstore FAT parition.

[knc1]

Originally Posted by eureka

BTW, for geeks: KT uses g_file_storage module (with parameter 'removable=y') for exporting it's "disk" as USB Mass Storage device.

Additional information:
http://git.kernel.org/?p=linux/kerne...2202de;hb=HEAD

Which is a view on: Documentation/usb/gadget_multi.txt in your kernel source tree.