On 2024-04-02, Esben Haabendal <esben@xxxxxxxxxx> wrote: >> printk() tries to print directly from the calling context. Are you >> experiencing problems where you do not see the restarting message? > > Yes, that is exactly what we are seing. > > It is an i.MX8MP system, and console is attached to ttymxc1 > (drivers/tty/serial/imx.c). > > Booting up, and simply executing "reboot" command. Without these two > patches, the "reboot: Restarting system" message is not written to > ttymxc1 console. With the patches, it is. This console driver is using the legacy console interface. For PREEMPT_RT, legacy consoles run exclusively as a thread and thus may not have a chance to flush messages before a shutdown/reboot. The correct solution is to port the driver to the new nbcon console interface. John Ogness
