Re: [PATCH 6/6] serial: 8250_dw: Ensure BUSY is deasserted

[John Ogness <john.ogness@linutronix.de>]

On 2026-01-27, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
>> > > +	if (d->in_idle) {
>> > 
>> > > +		/*
>> > > +		 * FIXME: this deadlocks if port->lock is already held
>> > > +		 * dev_err(p->dev, "Couldn't set LCR to %d\n", value);
>> > > +		 */
>> > 
>> > Hmm... That FIXME should gone since we have non-blocking consoles, no?
>> 
>> No, lockdep still gets angry if printing is used while holding port's 
>> lock.
>
> Hmm... Let's ask PRINTK people about this. John, do we still have a gap
> with nbcon? Or did I misunderstand the scope of its use?

The 8250 has not yet been converted to a nbcon. I am still working on
it. Unfortunately I got side-tracked first fixing the broken 8250
console hardware-flow-control support. :-/

So the comment is correct. Once the driver converts to nbcon, the
dev_err() is fine.

Note that if the message is important, you could use a printk_deferred()
here with a FIXME to say to convert it to dev_err() once the 8250
supports nbcon.

John Ogness