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

Wed Jul 23 13:19:08 UTC 2025

On Wed, Jul 23, 2025 at 12:38:08PM +0300, Imre Deak wrote:
> On Wed, Jul 23, 2025 at 02:59:46PM +0530, Dibin Moolakadan Subrahmanian wrote:
> > It has been observed that during `xe_display_pm_suspend()` execution,
> > an HPD interrupt can still be triggered, resulting in `dig_port_work`
> > being scheduled. The issue arises when this work executes after
> > `xe_display_pm_suspend_late()`, by which time the display is fully
> > suspended.
> > 
> > This can lead to errors such as "DC state mismatch", as the dig_port
> > work accesses display resources that are no longer available or
> > powered.
> > 
> > To address this, introduce  'intel_encoder_block_all_hpds' and
> > 'intel_encoder_unblock_all_hpds' functions, which iterate over all
> > encoders and block/unblock HPD respectively.
> > 
> > These are used to:
> > - Block HPD IRQs before calling 'intel_hpd_cancel_work' in suspend
> >   and shutdown
> > - Unblock HPD IRQs after 'intel_hpd_init' in resume
> > 
> > This will prevent 'dig_port_work' being scheduled during display
> > suspend.
> > 
> > Continuation of previous patch discussion:
> > https://patchwork.freedesktop.org/patch/663964/
> > 
> > Changes in v2:
> >  - Add 'intel_encoder_block_all_hpds' to 'xe_display_pm_shutdown'
> >  - Add 'intel_hpd_cancel_work' to 'xe_display_fini_early' to cancel
> >    any HPD pending work at late driver removal
> > 
> > Signed-off-by: Dibin Moolakadan Subrahmanian <dibin.moolakadan.subrahmanian at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_encoder.c | 23 ++++++++++++++++++++
> >  drivers/gpu/drm/i915/display/intel_encoder.h |  3 +++
> >  drivers/gpu/drm/i915/display/intel_hotplug.c |  2 --
> >  drivers/gpu/drm/xe/display/xe_display.c      |  6 +++++
> >  4 files changed, 32 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_encoder.c b/drivers/gpu/drm/i915/display/intel_encoder.c
> > index 0b7bd26f4339..4e2b77b87678 100644
> > --- a/drivers/gpu/drm/i915/display/intel_encoder.c
> > +++ b/drivers/gpu/drm/i915/display/intel_encoder.c
> > @@ -8,6 +8,7 @@
> >  #include "intel_display_core.h"
> >  #include "intel_display_types.h"
> >  #include "intel_encoder.h"
> > +#include "intel_hotplug.h"
> >  
> >  static void intel_encoder_link_check_work_fn(struct work_struct *work)
> >  {
> > @@ -37,6 +38,28 @@ void intel_encoder_link_check_queue_work(struct intel_encoder *encoder, int dela
> >  			 &encoder->link_check_work, msecs_to_jiffies(delay_ms));
> >  }
> >  
> > +void intel_encoder_unblock_all_hpds(struct intel_display *display)
> > +{
> > +	struct intel_encoder *encoder;
> > +
> > +	if (!HAS_DISPLAY(display))
> > +		return;
> > +
> > +	for_each_intel_encoder(display->drm, encoder)
> > +		intel_hpd_unblock(encoder);
> > +}
> > +
> > +void intel_encoder_block_all_hpds(struct intel_display *display)
> > +{
> > +	struct intel_encoder *encoder;
> > +
> > +	if (!HAS_DISPLAY(display))
> > +		return;
> > +
> > +	for_each_intel_encoder(display->drm, encoder)
> > +		intel_hpd_block(encoder);
> > +}
> > +
> >  void intel_encoder_suspend_all(struct intel_display *display)
> >  {
> >  	struct intel_encoder *encoder;
> > diff --git a/drivers/gpu/drm/i915/display/intel_encoder.h b/drivers/gpu/drm/i915/display/intel_encoder.h
> > index 3fa5589f0b1c..e1d3aeab7c00 100644
> > --- a/drivers/gpu/drm/i915/display/intel_encoder.h
> > +++ b/drivers/gpu/drm/i915/display/intel_encoder.h
> > @@ -17,4 +17,7 @@ void intel_encoder_link_check_flush_work(struct intel_encoder *encoder);
> >  void intel_encoder_suspend_all(struct intel_display *display);
> >  void intel_encoder_shutdown_all(struct intel_display *display);
> >  
> > +void intel_encoder_block_all_hpds(struct intel_display *display);
> > +void intel_encoder_unblock_all_hpds(struct intel_display *display);
> > +
> >  #endif /* __INTEL_ENCODER_H__ */
> > diff --git a/drivers/gpu/drm/i915/display/intel_hotplug.c b/drivers/gpu/drm/i915/display/intel_hotplug.c
> > index 265aa97fcc75..c69b535497bf 100644
> > --- a/drivers/gpu/drm/i915/display/intel_hotplug.c
> > +++ b/drivers/gpu/drm/i915/display/intel_hotplug.c
> > @@ -971,8 +971,6 @@ void intel_hpd_cancel_work(struct intel_display *display)
> >  
> >  	spin_lock_irq(&display->irq.lock);
> >  
> > -	drm_WARN_ON(display->drm, get_blocked_hpd_pin_mask(display));
> > -
> >  	display->hotplug.long_hpd_pin_mask = 0;
> >  	display->hotplug.short_hpd_pin_mask = 0;
> >  	display->hotplug.event_bits = 0;
> > 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>
> 
> >  	intel_dp_mst_suspend(display);
> >  	intel_hpd_cancel_work(display);
> >  
> > @@ -471,6 +475,8 @@ void xe_display_pm_resume(struct xe_device *xe)
> >  
> >  	intel_hpd_init(display);
> >  
> > +	intel_encoder_unblock_all_hpds(display);
> > +
> >  	if (has_display(xe)) {
> >  		intel_display_driver_resume(display);
> >  		drm_kms_helper_poll_enable(&xe->drm);
> > -- 
> > 2.43.0
> > 