Re: PREEMPT_RT vs i915

Ville Syrjälä
2025-07-09T20:09:26Z

On Wed, Jul 09, 2025 at 09:44:43PM +0200, Sebastian Andrzej Siewior wrote:
> On 2025-07-09 20:30:26 [+0300], Ville Syrjälä wrote:
> > >
> > > It seems like the critical uncore lock is currently held in a lot of
> > > places and potentially for a long time.
> >
> > It shouldn't be held for that long. I think it should just be
> > a raw spinlock.
>
> What about I resubmit the series and we look again? I don't think the
> lock should be made raw just to be done with it.

Until someone actually does the work to confirm the thing is working
reliably there's no point in posting anything.

And IIRC the other remaining problem with RT was the spinlocks used
inside tracepoints (which is uncore lock, and probably some vblank
locks). So that too needs some kind of solution because it's going to
very hard to debug the timing sensitive parts without the tracepoints.

--
Ville Syrjälä
Intel