On Fri, 5 Nov 2021, Mathias Nyman wrote:
> Hi
Hi, thanks for your help.
[...]
> > Plugging in the webcam produces the dmesg below.
> >
> > But unplugging simply results in no activity -- zero output in dmesg. Same
> > when plugging in again.
> >
> > After unplugging the device is still listed:
> >
> > $ lsusb
> > Bus 004 Device 002: ID 046d:0893 Logitech StreamCam
> > Bus 004 Device 001: ID 1d6b:0003 Linux 5.14.2-mh xhci-hcd xHCI Host Controller
> > Bus 003 Device 001: ID 1d6b:0002 Linux 5.14.2-mh xhci-hcd xHCI Host Controller
> > Bus 002 Device 001: ID 1d6b:0003 Linux 5.14.2-mh xhci-hcd xHCI Host Controller
> > Bus 001 Device 007: ID 046d:c52f Logitech USB Receiver
> > Bus 001 Device 006: ID 056a:037b Wacom Co.,Ltd. CTL-672
> > Bus 001 Device 005: ID 1a40:0101 USB 2.0 Hub
> > Bus 001 Device 004: ID 04d9:0340 USB-HID Keyboard
> > Bus 001 Device 003: ID 04d9:0339 USB-HID Keyboard
> > Bus 001 Device 002: ID 1a40:0101 USB 2.0 Hub
> > Bus 001 Device 001: ID 1d6b:0002 Linux 5.14.2-mh xhci-hcd xHCI Host Controller
>
> how about "lsusb -v"?
> It should try to read something from the device.
It seems to be populated with information from the webcam:
# lsusb -v
Couldn't open device, some information will be missing
Bus 004 Device 002: ID 046d:0893 Logitech StreamCam
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 3.20
bDeviceClass 239
[...]
but then on a second run, the webcam is removed from lsusb output.
Plugging it in again still has no effect.
[...]
> Normally xHC generates an interrupt at connect change, and the interrupt
> handler reads the port status, and prints a debugging message.
>
> We could manually read all the port registers before and after disconnecting.
> Check link state, and that the wake flags look ok in case device is suspended
>
> Example:
> # cat /sys/kernel/debug/usb/xhci/0000\:00\:14.0/ports/port*/portsc
> Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
> Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
> Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
> Powered Connected Enabled Link:U0 PortSpeed:3 Change: Wake:
> Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
> ...
There's no difference in the output before or after disconnecting the
camera:
stax# cat /sys/kernel/debug/usb/xhci/*/ports/port*/portsc
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
Powered Connected Enabled Link:U0 PortSpeed:3 Change: Wake:
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake: WCE WOE
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake: WCE WOE
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake: WCE WOE
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake: WCE WOE
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake: WCE WOE
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake: WCE WOE
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake: WCE WOE
Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake: WCE WOE
Powered Connected Enabled Link:Resume PortSpeed:15 OverCurrent In-Reset Change: CSC PEC WRC OCC PRC PLC CEC CAS Wake: WCE WDE WOE
Powered Connected Enabled Link:Resume PortSpeed:15 OverCurrent In-Reset Change: CSC PEC WRC OCC PRC PLC CEC CAS Wake: WCE WDE WOE
Powered Connected Enabled Link:Resume PortSpeed:15 OverCurrent In-Reset Change: CSC PEC WRC OCC PRC PLC CEC CAS Wake: WCE WDE WOE
Powered Connected Enabled Link:Resume PortSpeed:15 OverCurrent In-Reset Change: CSC PEC WRC OCC PRC PLC CEC CAS Wake: WCE WDE WOE
> Also see if disabling runtime suspend for both roothubs helps:
> # echo on > /sys/bus/usb/devices/usb1/power/control
> # echo on > /sys/bus/usb/devices/usb2/power/control
Yes, it helps. I pinpointed it on usb3. The webcam can now be plugged and
re-plugged. It also survives a suspend/resume of the machine now and I can
see the change in portsc:
-Powered Connected Enabled Link:U3 PortSpeed:4 Change: Wake:
+Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake:
So it seems this is a workaround -- thank you.
Is it worth getting to the root of this problem (and can I capture any
data to help?) or is it just that some devices are buggy?
Many thanks,
--
Mark
