On 2024-12-29, Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote: > On Fri, Dec 27, 2024 at 11:51:16PM +0106, John Ogness wrote: >> This is v4 of a series to convert the 8250 driver to an NBCON >> console, providing both threaded and atomic printing >> implementations. v3 of this series is here [0]. Additional >> background information about NBCON consoles in general is >> available in the cover letter of v2 [1]. > > Just to be sure I understand the side effect of this series, i.e. > the > > https://elixir.bootlin.com/linux/v6.13-rc3/source/drivers/tty/serial/8250/8250_port.c#L44 > https://elixir.bootlin.com/linux/v6.13-rc3/source/drivers/tty/serial/8250/8250_pci.c#L9 > > are not needed anymore (the first one can be replaced to something like > dev_dbg() or analogue)? Correct. With NBCON console drivers it is safe to call printk() while holding the port lock for non-console-printing purposes because: 1. printing via ->write_atomic() does not use the port lock and 2. printing via ->write_thread() is performed in a separate dedicated printing kthread that can safely spin on the port lock John
