On Wed, Jul 23, 2025 at 09:19:08AM -0400, Rodrigo Vivi wrote:
> 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.subrahman...@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 POV, merging it either via the i915 or xe branch is ok. Adding
Maarten.
> From my side I believe that any conflict might be easy to handle, so
>
> Acked-by: Rodrigo Vivi <rodrigo.v...@intel.com>
>
> from either side...
>
> >
> > Reviewed-by: Imre Deak <imre.d...@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
> > >
