Hi Felipe As far as I could see in Systemd, getty PID changes, so the SIGHUP should be received to close getty. The re-opening of the port with getty is when the issues begin. Regards Olivier Schonken On 1 March 2016 at 09:27, Felipe Balbi <balbi@xxxxxxxxxx> wrote: > > Hi, > > Robert Baldyga <r.baldyga@xxxxxxxxxxx> writes: >>> 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. > > there should be a SIGHUP when cable's removed, no ? > > -- > balbi -- 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
