Hi Tim,
On Tue, Jun 26, 2018 at 02:10:57PM +0200, Timur Krist?f wrote:
> > Can you send the dmesg output after you have plugged the powered and
> > non-powered hubs:
>
> Right now I have the Dell Type-C to USB 3.0 Type-A adapter with the USB
> 2.0 hub here. There is a Logitech received plugged into the hub. (So I
> can quickly see if it works or not.)
>
> After some trial-and-error I figured out when it works and when not.
> Tests were performed on Fedora 28 with kernel 4.17.2.
>
> Basically it always works just on the first try. In other words, when I
> power up the USB 2.0 hub and plug it in, then it works. If I plug it
> out, but keep it powered and plug it back in again, it stops working.
I wonder if the PD controller or EC firmware is seeing the
disconnection. Perhaps we can test it.
Can you check if have the USB Type-C ports and partners in sysfs
folder /sys/class/typec?
% ls /sys/class/typec/
port0 port0-partner port1
It may be that you need to cherry-pick a few patches from Greg's
tree [1][2] that fix an issue we had with the UCSI device on those
Dell laptops. Can you build your own kernel?
[1] https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git/commit/?h=usb-linus&id=d2d2e3c46be5d6dd8001d0eebdf7cafb9bc7006b
[2] https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git/commit/?h=usb-linus&id=1f9f9d168ce619608572b01771c47a41b15429e6
But if you can see the ports and partners under that sysfs folder,
after you unplug the device, does the port<x>-partner disappears?
> If it was plugged into another computer but kept powered, it does not
> work with this laptop either. (Until I power the hub off and on again.)
>
> It appears that the Thunderbolt and non-Thunderbolt ports behave
> slightly differently, and the same testcases leave wildly different
> messages in dmesg. So I will describe what I did and what output I got
> from dmesg.
Did you have a change to test if the problem can be reproduced in
Windows too?
FYI. I'll be travelling next week, so expect delays in my answers.
Br,
--
heikki
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