OTG and charging

Help Fairphone 3
,
1

Hello,

I’m looking for a way of using OTG while charging my phone.

My main goal is to use a DisplayLink adapter I have lying around to connect the phone to a bigger screen.

So I bought this ICZI hub, which confirmed me that OTG works (I tested Ethernet, USB and SD, they all work – DisplayLink works as expected, audio over HDMI included, while of course the HDMI out in the hub does nothing). Problem is: the phone does not charge with this hub. :frowning:

Is there anyone who found a way to use OTG while charging with Fairphone 3? Is this actually even possible?

Thanks!

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2

I doubt that OTG works. The FP3 has a USB-C port, but delivers only USB 2.0 through it.

Best wishes,
Thomas

3

OTG does work. The question was about charging while OTGing.

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4

“USB OTG is a part of a supplement to the Universal Serial Bus (USB) 2.0 specification originally agreed upon in late 2001 and later revised.”

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5

Hi serl,

I would have hoped this would work. Have you had a chance to, e.g., test another USB hub, or find another solution?

Sebastian.

6

Hello,
very much indeed!

TL;DR: I did not find a suitable solution, I’m sending the hubs back.

So, I tested another USB hub, with the same anecdotal result (no charging). I decided to perform some more rigorous tests. Here’s the parts list:

  • Fairphone 3 :slight_smile:
  • ICZI hub
  • UGREEN hub
  • A DisplayLink USB3 to HDMI adapter I bought in 2015, now at the same URL there’s a new model
  • Lenovo X1 Carbon and its 45W charger
  • A standard phone 5V/1A charger
  • Old TV with HDMI and USB

The test is about the time to discharge the battery from 85% to 80%. The phone was always in airplane mode, screen on, maximum brightness. When the DisplayLink was connected, its app was active, the TV was on and plugged (I mean, I could see the phone’s image* on it).

Configuration 1st test 2nd test
Fairphone 3 alone 28’47" 29’52"
Fairphone 3 + ICZI hub 10’42" 10’41"
Fairphone 3 + UGREEN hub 13’53"
Fairphone 3 + ICZI + DisplayLink 4’18" 5’20"
Fairphone 3 + UGREEN + DisplayLink 6’26" 7’30"
Fairphone 3 + ICZI + DisplayLink + 45W charger 37’45" 28’47"
Fairphone 3 + UGREEN + DisplayLink + 45W charger 27’45" 30’54"
Fairphone 3 + ICZI + DisplayLink + phone charger 28’15" 30’55"
Fairphone 3 + UGREEN + DisplayLink + phone charger 24’30" 27’43"
Fairphone 3 + ICZI + DisplayLink + computer USB 25’37" 27’44"
Fairphone 3 + UGREEN + DisplayLink + computer USB 27’45" 25’38"
Fairphone 3 + ICZI + DisplayLink + TV USB 32’00" 28’50"
Fairphone 3 + UGREEN + DisplayLink + TV USB 30’56" 27’44"

You can see that anything plugged to the charging port of the hubs will help to avoid ultra-fast discharge. Also, in this case, size does not matter! Old TV USB port was enough.

Also, maybe important: even the PC does not charge with these hubs (PC<-hub<-45W charger)! No idea why.

My conclusion: I’m probably better off with some wireless screen sharing.

* In case you’re wondering: no, “Experimental desktop mode” does not work with DisplayLink, it is only mirroring.

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Nice work, thanks for the patience it cost you. :slightly_smiling_face:

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8

I have the same problem with some ethernet adapters like This or This.

What I find out is, it looks like that CONFIG_USB_MSM_ACA in drivers/usb/otg/msm_otg is not enabled, but for that you have to compile a new kernel.

I don’t know I’m on the right way, but this is all what I can find out.

Both adapters works fine on a Samsung Galaxy Tablet, so while charging, I have also Ethernet simultaneous. On the FP3, on one adapter Ethernet is working, with the other adapter it flapping every 5 seconds between charging and Ethernet.

9

Following scenario: you have a device that is capable of presenting your phone’s screen, but it also has an additional USB port to supply power as well as act as a USB hub for peripherals.

Is it generally possible to get your Fairphone 3 to run on display link while being charged using a y cable with one USBC port on one end and a USB A and USB C port on the other to fulfill that task?

I would be curious to know.

10

I moved your post here to avoid duplicate topics.
Seems there’s no solution in sight yet, but there’s some info nonetheless.