[PATCH v2] drm/xe/display: Block hpd during suspend

[Imre Deak]

On Tue, Jul 29, 2025 at 10:35:48AM -0400, Rodrigo Vivi wrote:
> On Tue, Jul 29, 2025 at 12:44:47PM +0300, Jani Nikula wrote:
> > On Thu, 24 Jul 2025, Maarten Lankhorst <maarten.lankhorst at linux.intel.com> wrote:
> > > Hey,
> > > [...]
> > >>>> diff --git a/drivers/gpu/drm/xe/display/xe_display.c b/drivers/gpu/drm/xe/display/xe_display.c
> > >>>> index e2e0771cf274..9e984a045059 100644
> > >>>> --- a/drivers/gpu/drm/xe/display/xe_display.c
> > >>>> +++ b/drivers/gpu/drm/xe/display/xe_display.c
> > >>>> @@ -96,6 +96,7 @@ static void xe_display_fini_early(void *arg)
> > >>>>  	if (!xe->info.probe_display)
> > >>>>  		return;
> > >>>>  
> > >>>> +	intel_hpd_cancel_work(display);
> > >>>>  	intel_display_driver_remove_nogem(display);
> > >>>>  	intel_display_driver_remove_noirq(display);
> > >>>>  	intel_opregion_cleanup(display);
> > >>>> @@ -340,6 +341,8 @@ void xe_display_pm_suspend(struct xe_device *xe)
> > >>>>  
> > >>>>  	xe_display_flush_cleanup_work(xe);
> > >>>>  
> > >>>> +	intel_encoder_block_all_hpds(display);
> > >>>> +
> > >>>>  	intel_hpd_cancel_work(display);
> > >>>>  
> > >>>>  	if (has_display(xe)) {
> > >>>> @@ -369,6 +372,7 @@ void xe_display_pm_shutdown(struct xe_device *xe)
> > >>>>  	}
> > >>>>  
> > >>>>  	xe_display_flush_cleanup_work(xe);
> > >>>> +	intel_encoder_block_all_hpds(display);
> > >>>
> > >>> MST still needs HPD IRQs for side-band messaging, so the HPD IRQs must
> > >>> be blocked only after intel_dp_mst_suspend().
> > >>>
> > >>> Otherwise the patch looks ok to me, so with the above fixed and provided
> > >>> that Maarten is ok to disable all display IRQs only later:
> > >> 
> > >> Also probably good to identify the patch as both xe and i915 in the subject
> > >> drm/{i915,xe}/display:
> > >> 
> > >> and Maarten or Imre, any preference on which branch to go? any chance of
> > >> conflicting with any of work you might be doing in any side?
> > >> 
> > >> From my side I believe that any conflict might be easy to handle, so
> > >> 
> > >> Acked-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> > >> 
> > >> from either side...
> > >> 
> > >>>
> > >>> Reviewed-by: Imre Deak <imre.deak at intel.com>
> > > We had a discussion on this approach, and it seems that completely disabling interrupts here like in i915 would fail too.
> > >
> > > Reviewed-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> > >
> > > I don't mind either branch. As long as it applies. :-)
> > 
> > Please do not merge through *any* tree.
> > 
> > How come you all think it's okay to add this xe specific thing, and make
> > unification harder?
> 
> I lost any moral or rights to complain here since I couldn't move with my
> tasks of unification of the pm flow :(
> 
> double sorry!
> 
> > 
> > intel_encoder_block_all_hpds() is *way* too specific for a high level
> > function. Neither xe nor i915 should never call something like that
> > directly.
> 
> that's a valid point indeed. But I cannot see another way to fix the
> current issue right now without trying to move with the full unification
> faster. Do you?

Imo, this should be fixed first in xe without affecting i915. Then a
related fix would be needed in i915, which disables all display IRQs too
early now, as in:

https://github.com/ideak/linux/commit/0fbe02b20e062

After that the xe and i915 system suspend/resume and shutdown sequences
could be unified mostly. Fwiw I put together that now on top of Dibin's
patch:

https://github.com/ideak/linux/commits/suspend-shutdown-refactor

> > 
> > BR,
> > Jani.
> > 
> > 
> > -- 
> > Jani Nikula, Intel