Re: [PATCH] serial: core: Fix probing serial_base_bus devices

[Tony Lindgren <tony@atomide.com>]

* Greg Kroah-Hartman <gregkh@linuxfoundation.org> [230601 14:21]:
> On Thu, Jun 01, 2023 at 05:14:44PM +0300, Tony Lindgren wrote:
> > If a physical serial port device driver uses arch_initcall() we fail to
> > probe the serial_base_bus devices and the serial port tx fails. This is
> > because as serial_base_bus uses module_initcall().
> > 
> > Let's fix the issue by changing serial_base_bus to use arch_initcall().
> 
> This will only work if the linking order is such that this will always
> come before the drivers.  Is that the case here?

I guess based on Makefile. And also if serial drivers are modules as we
export uart_add_one_port() from serial_base.ko. But yeah this is pretty
fragile potentially.

Hmm maybe we could keep module_init() and then also call serial_base_init()
on uart_add_one_port() path if not yet initialized?

Probably the module_init() should be still there for case when no serial
port device drivers are loaded and serial_base is unloaded..

Regards,

Tony