Hi Oliver, On 02/29/2016 08:34 AM, Felipe Balbi wrote: > > Hi, > > Olivier Schonken <olivier.schonken@xxxxxxxxx> writes: >> Hope I'm not raising an issue which actually is my own stupidity. >> >> I recently upstreamed my embedded Linux kernel to version 4.4, after which >> I started experiencing issues with my serial gadget - acm and obex. I used >> to be able to run a getty console on it through a systemd service, which >> would restart everytime it was unplugged, and plugged in again. With >> kernel 4.4, this stopped working as usual(On startup console would word, >> but if plugged out and in again, console is frozen), and I traced it back >> to the series of patches "usb: gadget: introduce 'enabled' flag in struct >> usb_ep". If I revert these patches, everything works as normal again. As >> you are the owner of these patches, I thought that you might help me >> understand if I'm doing something wrong w.r.t. re-initializing the console >> getty, or if something really got broken. > > This is short of email where the mailing list should be in Cc :-) > > The author of that series was Robert (now in Cc). Robert, does this ring > any bells to you ? > I have tested it with getty (without systemd) and it looks like getty hangs up after replugging no matter if patch is applied or not, so without systemd it won't work anyway. Hence how systemd handles this is the key here, however I have no idea how systemd knows that USB device is unplugged. On device side /dev/ttyGS0 exists regardless to ACM function state, so process which opened this device file has no way to figure out whether connection to host is active or not. Can you explain how systemd knows that device is unplugged? This knowledge can be helpful. And one more thing - are you using configfs of legacy gadget? This could help to reproduce the problem. Best regards, Robert -- 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
