| Message ID | 20250702143209.3345301-1-ernest.vanhoecke@toradex.com |
|---|---|
| State | Under Review |
| Headers | show |
| Series | [meta-oe] libusbgx: exit with failure code when no UDC is detected | expand |
diff --git a/meta-oe/recipes-support/libusbgx/libusbgx/gadget-start b/meta-oe/recipes-support/libusbgx/libusbgx/gadget-start index e80cb2c34068..4ef679888ec4 100755 --- a/meta-oe/recipes-support/libusbgx/libusbgx/gadget-start +++ b/meta-oe/recipes-support/libusbgx/libusbgx/gadget-start @@ -15,6 +15,10 @@ for i in $ENABLED_SCHEMAS; do if [ -n "${configured_udc}" ] && [ -e "/sys/class/udc/${configured_udc}" ]; then echo ${configured_udc} > /sys/kernel/config/usb_gadget/"$i"/UDC else - ls /sys/class/udc/ > /sys/kernel/config/usb_gadget/"$i"/UDC + detected_udc=$(ls /sys/class/udc/) + if [ -z "${detected_udc}" ]; then + exit 1 + fi + echo "${detected_udc}" > /sys/kernel/config/usb_gadget/"$i"/UDC fi done
The systemd target `usb-gadget.target` is triggered by udev when a UDC first comes up. It can happen that by the time gadget-start runs, this UDC has been removed from the system again. Have the gadget-start script exit with status 1 when `ls /sys/class/udc` returns nothing. Causing a service failure when no UDC is detected and no default was given, allows the service to be restarted by a udev rule calling the service (and not the target since those are not reentrant) directly. On its own this patch will not do much. For example, we saw such a situation using the DWC3 USB controller and usb-conn-gpio kernel modules as loadables. By the time of the DWC3 init, udev was active, and during init DWC3 started the USB OTG port in device mode. If a pen drive was plugged in at boot, it would quickly switch to host mode right after initialisation, emitting another udev event for the removal of the UDC. The systemd target as thus reached, but by the time gadget-start ran, the UDC was gone. dwc3 init usb-conn-gpio role switch │ │ ▼ ▼ udev: add UDC─┐ udev: del UDC─────►/sys/class/udc empty │ │ │ x │ │ │ ▼ └────────────►usb-gadget.target─────►gadget-start Signed-off-by: Ernest Van Hoecke <ernest.vanhoecke@toradex.com> --- meta-oe/recipes-support/libusbgx/libusbgx/gadget-start | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)