Re: [PATCH] ns16550: ensure polling timer is disarmed

[dmkhn@xxxxxxxxx]

On Wed, Jul 30, 2025 at 10:12:54AM +0200, Jan Beulich wrote:
> On 30.07.2025 05:13, dmkhn@xxxxxxxxx wrote:
> > From: Denis Mukhin <dmukhin@xxxxxxxx>
> >
> > As it stands, polling timer is kept in the list of timers even after the
> > interrupts have been enabled / polling disabled on ns16550-compatible UART.
> >
> > Ensure polling timer is removed from the timer list once UART interrupts are
> > enabled.
> >
> > Signed-off-by: Denis Mukhin <dmukhin@xxxxxxxx>
> 
> Wasn't it Andrew(?) who suggested something along these lines? That would
> want reflecting by a tag then.

Yes, indeed.

> 
> Also, what's the real problem you want to solve here? The timer function
> would be run one more time after ->intr_works is set, and then the timer
> will be permanently inactive (up to a possible S3 resume). Is it being on
> an inactive list an actual problem? (IOW I'd like to understand if the
> change is merely cosmetic, or if there is some actual benefit.)

My understanding is running polling timer one more time after the interrupts
are enabled is the issue: if there's a pending timer when it is known the
timer not needed, then the timer should be canceled.

> 
> Jan