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-   -   charging via USB, data connection not entirely terminated? (https://www.linuxquestions.org/questions/linux-hardware-18/charging-via-usb-data-connection-not-entirely-terminated-668350/)

vimico 09-08-2008 07:10 AM

charging via USB, data connection not entirely terminated?
 
I have a minor problem with my MP3/MP4 player "Technaxx TouchMe":

http://www.linuxquestions.org/hcl/sh...t/4196/cat/all

The device is being charged via USB.

It only switches into charging mode, if no computer is detected on the other side of the USB cable, i.e. I have to use the enclosed main adapter with its built-in USB socket.

If I unmount the device under Linux (Gnome, Ubuntu Hardy), the device remains in some kind of data link stand-by mode after the buffer is flushed.

If I repeat the same procedure under Windows, the device switches to charging mode after I have unmounted the device.

I wonder if this is a know 'problem', and if there is some way to fix it.

(Perhaps HAL or udev haven't released it fully....)

MS3FGX 09-08-2008 10:28 AM

The same thing happens with iPods. Try running the "eject" command against the device node (I.E. eject /dev/sda) and see if that puts it into charging mode or not.

Electro 09-08-2008 04:08 PM

I assume it is a storage device. Remove the module usb-storage. It should then start recharging. Another way is re-wire a USB cable that does not have its data pins connected, but only the power pins.

vimico 09-10-2008 11:04 AM

eject:
This was my first idea as well, but it did not work.

unloading usb-storage:
Interesting. Sounds a bit like solving the problem by killing the patient :-) Well, it did not work either.

However:
Unloading the modules ehci_hcd and/or uhci_hcd did help. And you can modprobe them back into the kernel to restore normal functionality.

According to Google, these modules are responsible for USB 2.0 and USB 1.1 resp.

This is a work around but not a fix, as it effects all other USB connections as well.


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