On Tue, 2019-08-20 at 17:27 -0700, Jason Wessel wrote: > Some BSPs use a USB serial port which may or may not actually be > plugged all the time. It is quite useful to have a USB serial port > have a getty running but it does not make sense to wait for it for 90 > seconds before completing the system startup if it might never get > plugged in. The typical example is that a USB serial device might > only need to be plugged in when debugging, upgrading, or initially > configuring a device. > > This change is somewhat subtle. Systemd uses the "BindsTo" directive > to ensure existence of the device in order to start the service as > well as to terminate the service if the device goes away. The > "After" > directive makes that same relationship stronger, and has the > undesired > side effect that systemd will wait until its internal time out value > for the device to come on line before executing a fail operation or > letting other tasks and groups continue. This is certainly the kind > of behavior we want for a disk, but not for serial ports in general. > > The kernel module loader and device detection will have run a long > time before the getty startup. By the time the getty startup occurs > the system has all the serial devices its going to get. > > If you want to observe the problem with qemu, it is easy to > replicate. > Simply add the following line to your local.conf for a x86-64 qemu > build. > > SERIAL_CONSOLES="115200;ttyS0 115200;ttyUSB0" > > Login right after the system boots and observe: > > root@qemux86-64:~# systemctl list-jobs |cat > JOB UNIT TYPE STATE > 1 multi-user.target start waiting > 69 serial-getty@ttyUSB0.service start waiting > 64 getty.target start waiting > 71 dev-ttyUSB0.device start running > 62 systemd-update-utmp-runlevel.service start waiting > > 5 jobs listed. > > You can see above that the dev-ttyUSB0.device will block for 1min 30 > seconds. While that might not be a problem for this reference build. > It is certainly a problem for images that have software watchdogs > that > verify the system booted up all the way to systemd completion in less > than 90 seconds. > > This other nice effect of this change is that the fast fail device > extend to additional serial ports that may not exist on ARM BSPs or > that might be configured in or out by the dtb files on different > boards. > > Signed-off-by: Jason Wessel <jason.wes...@windriver.com> > --- > .../systemd/systemd-serialgetty/serial-getty@.service | 2 > +- > 1 file changed, 1 insertion(+), 1 deletion(-)
Hi Jason, Somehow this change is responsible for this build failure: https://autobuilder.yoctoproject.org/typhoon/#/builders/72/builds/976 (steps 5c and 7c so failure during testimage). I have bisected it to this change, I haven't looked into why. Cheers, Richard -- _______________________________________________ Openembedded-core mailing list Openembedded-core@lists.openembedded.org http://lists.openembedded.org/mailman/listinfo/openembedded-core