Thinkpad 10 tablet keeps supplying usb power even when switched off??


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Hello again,

I am attempting to use my thinkpad 10 tablet ( Windows) as a car front end.

I am getting there ( :) ), but am still stuck by some problems.

One of these is power management.

I have various peripherals connected via a separately powered usb hub.

so........ I don't need any power to the hub from the tablet.

If I am not going to be away from the car for long, rather than shutting down the tab, I sleep it .

Althougth power to the tab and the powered hub is removed, the tablet still gives power to the hub from its battery reserve.

The hub has seven peripherals attached, so it can represent quite a drain to the tablet on battery.

I have tried to prevent usb ( selective suspend), and also tried to check for windows powering down any usb devices to save power in Device Manager.

Still, every time the car removes power, the usb port on the tablet is still active??

Has anybody any ideas?

-- by the way, I have no option in BIOS for usb power, and I also tried to make a USB cable DATA only- no luck ------

Many Thanks

Pootler
 
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Regedit32

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Can you clarify something regarding your efforts in Device Manager please.

When you go into Device Manager, and expand the Universal Serial Bus Controllers, then right-click on the USB Root Hub entries and select properties, and now select the Power Management tab, are you removing the check next to 'Allow the computer to turn off this device to save power'?

Sample image

1578430375778.png
 
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HI,

Thanks for the reply

I am leaving the relevant box(es) CHECKED.

Doesn't appear to make any difference.

The thinkpad's BIOS settings are also basic, with no mention of USB power management.

Thanks again

pootler
 
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Didn't find much at Lenovo on that model but some portables are coming with USB ports that provide charging power for other devices such as SmartPhones, may be the cause of the port/s supplying power even when supposedly off.
 
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Hi,

Thanks for the reply

Its a ThinkPad 10 (Type 20C1, 20C3).

It's quite old ( 2014/15), but still runs win 10 good enough for a carputer :)

As mentioned, there is no info in the manual, and the BIOS is very limited, with no BIOS power mangement.


I guess there's no harm mailing lenovo, but they don't usually deal with non-warranted products.

Thanks again

pootler
 

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