Hi Heikki, On Fri, 2018-06-29 at 14:42 +0300, Heikki Krogerus wrote: > 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. How does the PD controller come into the picture? (Assuming you mean PD = Power Delivery?) The device I was talking about does not (and should not) deliver any power to the laptop. Again this is a powered USB 2.0 hub with the Dell Type-C to Type-A adapter, so it does not support PD. (Next week I will buy a Type-C hub with PD support so will be able to test with that too.) > > 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 On kernel 4.17.2 (as packaged by Fedora 28), that directory is empty, even though I have something plugged in to all ports. > 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/co > mmit/?h=usb-linus&id=d2d2e3c46be5d6dd8001d0eebdf7cafb9bc7006b > [2] https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git/co > mmit/?h=usb-linus&id=1f9f9d168ce619608572b01771c47a41b15429e6 How I usually build a kernel is I just use Fedora's config and tools, ie. I patch the latest Fedora kernel and build it using 'fedpkg' locally. Hope this approach is OK. Now I got the latest from the f28 branch (which is 4.17.3 with some patches). I added the two patches from above. With the patched kernel, the directory is non-empty but it does not correctly react to hotplugging and unplugging. > But if you can see the ports and partners under that sysfs folder, > after you unplug the device, does the port<x>-partner disappears? When I have something in every port on bootup I see this: $ ls /sys/class/typec/ port0 port0-partner port1 port1-partner port2 port2-partner But when I boot the machine with nothing plugged in, and then plug the things in later: - Type-C adapter with the USB 2.0 hub does not get a "partner" when it is hotplugged, only when it is plugged in at boot time. The partner correctly disappears when I plug it out but never appears again. - Type-C charger appears as a "partner" when hot-plugged, but the partner does not disappear even if I plug it out. Despite this, charging continues to work when I plug it back in to any port. Though no other partner gets created when I plug it into a different port. Note that despite the presence of the "partner" Linux still recognizes that the laptop is not charging, when the charger is plugged out. - Type-C to DisplayPort adapter also shows up as a partner only when it is present at boot time. Otherwise not. However it still works with any of the three Type-C ports. > > > 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? Sorry, not yet but I will get around to it next week. (The XPS is my primary work machine so I will have to back up everything before trying my luck with Windows.) > FYI. I'll be travelling next week, so expect delays in my answers. I hope you have a great time! Best regards, Tim -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
