Hi,
we have a number b210s that has USB detect problems. We have equipment where
the power can suddenly disappear, and then the system does not come up right
and there is (yet) no programmatic way to resolve the problem, so we have to
get in physical contact with the system.
Any one who knows of a workaround (pls. read below before answering)…
*PC cannot detect B210 USB device on cold boot (after for instance a power
break)
*The B210 USB device is simply not recognized by the PC.
*The B210 has an attached GPSDO and external power attached.
*This happens on multiple systems and cannot be attributed to a single PC type
nor B210 device.
Steps to reproduce:
1. Remove all power from PC and B210.
2. Insert USB into PC.
3. Apply power to the devices.
4. Start the PC.
5. The PC is after boot into linux to see the B210 board.
6. Errors are displayed in the dmesg kernel log:
[ 23.884317] usb 1-4: new high-speed USB device number 3 using xhci_hcd [
29.024313] usb 1-4: device descriptor read/64, error -110 [ 44.640330] usb
1-4: device descriptor read/64, error -110 [ 44.748356] usb usb1-port4:
attempt power cycle [ 45.400311] usb 1-4: new high-speed USB device number 4
using xhci_hcd [ 56.240225] usb 1-4: device not accepting address 4, error
-62 [ 56.368230] usb 1-4: new high-speed USB device number 5 using xhci_hcd [
66.992306] usb 1-4: device not accepting address 5, error -62 [ 66.992363]
usb usb1-port4: unable to enumerate USB device
The "device descriptor read/64, error -110" means that USB power drain was
exceeded by the USB device.
7. Our application prints:
Error: LookupError: KeyError: No devices found for -----> Device Address:
num_recv_frames: 512
8. The device is totally absent, so its not possible to for instance run:
$UHD_INSTALL_PREFIX/utils/b2xx_fx3_utils --reset-device
Workarounds that works:
* Physically unplug the USB device and insert it again in the same USB port.
(sometimes it though seems like this does not work either, and one need to
switch to a new USB port on another USB HUB on the PC)
* Physically press the reset switch (S700) on the B210.
* Remove external power supply from B210 before cold boot.
Workarounds that haven't worked:
* Rebooting the PC, by software and/or by physically switching it off and then
on (power cable off and on).
* Try to programmatically remove power from USB device:
lsusb
echo suspend > sudo tee /sys/bus/usb/devices/usb1/power/level
echo suspend > sudo tee /sys/bus/usb/devices/usb2/power/level
lsusb
echo on > sudo tee /sys/bus/usb/devices/usb1/power/level
echo on > sudo tee /sys/bus/usb/devices/usb2/power/level
lsusb
* Try to remove the highspeed USB driver:
lsusb
echo "0000:00:14.0" | sudo tee /sys/bus/pci/drivers/xhci_hcd/unbind
lsusb
dmesg
echo "0000:00:14.0" | sudo tee /sys/bus/pci/drivers/xhci_hcd/bind
lsusb
* Remove and re-enumerate the USB controller PCI device:
lsusb
lspci
echo 1 | sudo tee /sys/devices/pci0000\:00/0000\:00\:14.0/remove
lsusb
lspci
echo 1 | sudo tee /sys/bus/pci/rescan
lsusb
lspci
Workarounds that haven't been tried:
* Use an USB3 hub that is externally powered.
* Install a larger capacitor in parallel with C716/S700 on the B210 board to
delay USB startup by the device. Somebody recall installing a 100uF capacitor.
But this doesn’t seem like a root cause fix.
* Circumvent power switching components (solder a short over Q600) such that
external power is always used and not disconnected before any USB
communication. Any side effects ?
Root cause:
We believe the root cause is the switching between USB and external power, in
the LTC4412 U609 circuit. If external power is removed before cold boot, the
device comes up correctly while external B210 power is not attached.
Also worth noting, is that this may only happen when a GPSDO is attached. We
haven't tried removing the GPSDO, since it is rather fragile.
Another “malicious” behavior is when external power is on and USB is attached
then Q600 will go on if it is not already on. When USB is removed Q600 will
stay on, ie. the circuitry will not come back to the state it had when
everything was powered on from scratch.
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