On Thu, Sep 05, 2024 at 03:53:17PM +0206, John Ogness wrote: > The recent printk rework introduced a new type of console NBCON > that will perform printing via a dedicated kthread during > normal operation. For times when the kthread is not available > (early boot, panic, reboot/shutdown) the NBCON console will > print directly from the printk() calling context (even if from > NMI). > > Futher details about NBCON consoles are available here [0]. > > This series converts the 8250 driver to an NBCON console, > providing both threaded and atomic printing implementations. > Users can verify the UART console is an NBCON console via the > proc filesystem. For example: > > $ cat /proc/consoles > ttyS0 -W- (EC N a) 4:64 > > The 'N' shows that it is an NBCON console. > > There will also be a dedicated printing kthread. For example: > > $ ps ax | grep pr/ > 16 root 0:00 [pr/ttyS0] Wondering if this can use the DEVNAME instead of opaque (to some extent) ttySx? Or is it using the same what has been passed to the console= kernel command line parameter? > Derek Barbosa performed extensive tests [1] using this driver > and encountered no issues. On the contrary, his tests showed > the improved reliability and non-interference features of the > NBCON-based driver. > > Since this is the first console driver to be converted to an > NBCON console, it may include variables and functions that > could be abstracted to all UART consoles (such as the > @console_newline_needed field). However, we can abstract such > things later as more consoles are converted to NBCON. > > John Ogness > > [0] https://lore.kernel.org/lkml/20230302195618.156940-1-john.ogness@xxxxxxxxxxxxx > [1] https://lore.kernel.org/lkml/ZsdoD6PomBRsB-ow@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx -- With Best Regards, Andy Shevchenko
