Re: [PATCH v8 4/4] drm/xe/gt: Introduce runtime suspend/resume

[Raag Jadav <raag.jadav@intel.com>]

On Tue, Nov 04, 2025 at 09:47:10AM -0800, Matthew Brost wrote:
> On Thu, Oct 30, 2025 at 05:53:57PM +0530, Raag Jadav wrote:
> > If power state is retained between suspend/resume cycle, we don't need
> > to perform full GT re-initialization. Introduce runtime helpers for GT
> > which greatly reduce suspend/resume delay.
> > 
> > v2: Drop redundant xe_gt_sanitize() and xe_guc_ct_stop() (Daniele)
> >     Use runtime naming for guc helpers (Daniele)
> > v3: Drop redundant logging, add kernel doc (Michal)
> >     Use runtime naming for ct helpers (Michal)
> > v4: Fix tags (Rodrigo)
> > v5: Include host_l2_vram workaround (Daniele)
> >     Reuse xe_guc_submit_enable/disable() helpers (Daniele)
> > 
> > Co-developed-by: Riana Tauro <riana.tauro@intel.com>
> > Signed-off-by: Riana Tauro <riana.tauro@intel.com>
> > Signed-off-by: Raag Jadav <raag.jadav@intel.com>
> > Acked-by: Matthew Brost <matthew.brost@intel.com>
> > Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > ---
> >  drivers/gpu/drm/xe/xe_gt.c     | 60 ++++++++++++++++++++++++++++++++++
> >  drivers/gpu/drm/xe/xe_gt.h     |  2 ++
> >  drivers/gpu/drm/xe/xe_guc.c    | 34 +++++++++++++++++++
> >  drivers/gpu/drm/xe/xe_guc.h    |  2 ++
> >  drivers/gpu/drm/xe/xe_guc_ct.c | 27 +++++++++++++++
> >  drivers/gpu/drm/xe/xe_guc_ct.h |  2 ++
> >  drivers/gpu/drm/xe/xe_pm.c     | 10 +++---
> >  drivers/gpu/drm/xe/xe_uc.c     | 28 ++++++++++++++++
> >  drivers/gpu/drm/xe/xe_uc.h     |  2 ++
> >  9 files changed, 162 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/xe/xe_gt.c b/drivers/gpu/drm/xe/xe_gt.c
> > index 89808b33d0a8..0c300f8dd588 100644
> > --- a/drivers/gpu/drm/xe/xe_gt.c
> > +++ b/drivers/gpu/drm/xe/xe_gt.c
> > @@ -1008,6 +1008,66 @@ int xe_gt_resume(struct xe_gt *gt)
> >  	return err;
> >  }
> >  
> > +/**
> > + * xe_gt_runtime_suspend() - GT runtime suspend
> > + * @gt: the GT object
> > + *
> > + * Return: 0 on success, negative error code otherwise.
> > + */
> > +int xe_gt_runtime_suspend(struct xe_gt *gt)
> > +{
> > +	unsigned int fw_ref;
> > +	int err = -ETIMEDOUT;
> > +
> > +	xe_gt_dbg(gt, "runtime suspending\n");
> > +
> > +	fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FORCEWAKE_ALL);
> > +	if (!xe_force_wake_ref_has_domain(fw_ref, XE_FORCEWAKE_ALL))
> > +		goto err_force_wake;
> > +
> > +	xe_uc_runtime_suspend(&gt->uc);
> > +	xe_gt_disable_host_l2_vram(gt);
> > +
> > +	xe_force_wake_put(gt_to_fw(gt), fw_ref);
> > +	xe_gt_dbg(gt, "runtime suspended\n");
> > +
> > +	return 0;
> > +
> > +err_force_wake:
> > +	xe_force_wake_put(gt_to_fw(gt), fw_ref);
> > +	return err;
> > +}
> > +
> > +/**
> > + * xe_gt_runtime_resume() - GT runtime resume
> > + * @gt: the GT object
> > + *
> > + * Return: 0 on success, negative error code otherwise.
> > + */
> > +int xe_gt_runtime_resume(struct xe_gt *gt)
> > +{
> > +	unsigned int fw_ref;
> > +	int err = -ETIMEDOUT;
> > +
> > +	xe_gt_dbg(gt, "runtime resuming\n");
> > +
> > +	fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FORCEWAKE_ALL);
> > +	if (!xe_force_wake_ref_has_domain(fw_ref, XE_FORCEWAKE_ALL))
> > +		goto err_force_wake;
> > +
> > +	xe_gt_enable_host_l2_vram(gt);
> > +	xe_uc_runtime_resume(&gt->uc);
> > +
> > +	xe_force_wake_put(gt_to_fw(gt), fw_ref);
> > +	xe_gt_dbg(gt, "runtime resumed\n");
> > +
> > +	return 0;
> > +
> > +err_force_wake:
> > +	xe_force_wake_put(gt_to_fw(gt), fw_ref);
> > +	return err;
> > +}
> > +
> >  struct xe_hw_engine *xe_gt_hw_engine(struct xe_gt *gt,
> >  				     enum xe_engine_class class,
> >  				     u16 instance, bool logical)
> > diff --git a/drivers/gpu/drm/xe/xe_gt.h b/drivers/gpu/drm/xe/xe_gt.h
> > index 9d710049da45..94969ddd9d88 100644
> > --- a/drivers/gpu/drm/xe/xe_gt.h
> > +++ b/drivers/gpu/drm/xe/xe_gt.h
> > @@ -58,6 +58,8 @@ int xe_gt_suspend(struct xe_gt *gt);
> >  void xe_gt_shutdown(struct xe_gt *gt);
> >  int xe_gt_resume(struct xe_gt *gt);
> >  void xe_gt_reset_async(struct xe_gt *gt);
> > +int xe_gt_runtime_resume(struct xe_gt *gt);
> > +int xe_gt_runtime_suspend(struct xe_gt *gt);
> >  void xe_gt_sanitize(struct xe_gt *gt);
> >  int xe_gt_sanitize_freq(struct xe_gt *gt);
> >  
> > diff --git a/drivers/gpu/drm/xe/xe_guc.c b/drivers/gpu/drm/xe/xe_guc.c
> > index ecc3e091b89e..ee35f1d8c21b 100644
> > --- a/drivers/gpu/drm/xe/xe_guc.c
> > +++ b/drivers/gpu/drm/xe/xe_guc.c
> > @@ -1607,6 +1607,40 @@ int xe_guc_start(struct xe_guc *guc)
> >  	return xe_guc_submit_start(guc);
> >  }
> >  
> > +/**
> > + * xe_guc_runtime_suspend() - GuC runtime suspend
> > + * @guc: The GuC object
> > + *
> > + * Stop further runs of submission tasks on given GuC and runtime suspend
> > + * GuC CT.
> > + */
> > +void xe_guc_runtime_suspend(struct xe_guc *guc)
> > +{
> > +	xe_guc_submit_pause(guc);
> > +	xe_guc_submit_disable(guc);
> > +	xe_guc_ct_runtime_suspend(&guc->ct);
> > +}
> > +
> > +/**
> > + * xe_guc_runtime_resume() - GuC runtime resume
> > + * @guc: The GuC object
> > + *
> > + * Runtime resume GuC CT and allow further runs of submission tasks on
> > + * given GuC.
> > + */
> > +void xe_guc_runtime_resume(struct xe_guc *guc)
> > +{
> > +	/*
> > +	 * Runtime PM flows are not applicable for VFs, so it's safe to
> > +	 * directly enable IRQ.
> > +	 */
> > +	guc_enable_irq(guc);
> > +
> > +	xe_guc_ct_runtime_resume(&guc->ct);
> > +	xe_guc_submit_enable(guc);
> > +	xe_guc_submit_unpause(guc);
> > +}
> > +
> >  void xe_guc_print_info(struct xe_guc *guc, struct drm_printer *p)
> >  {
> >  	struct xe_gt *gt = guc_to_gt(guc);
> > diff --git a/drivers/gpu/drm/xe/xe_guc.h b/drivers/gpu/drm/xe/xe_guc.h
> > index e2d4c5f44ae3..fdb08658d05a 100644
> > --- a/drivers/gpu/drm/xe/xe_guc.h
> > +++ b/drivers/gpu/drm/xe/xe_guc.h
> > @@ -35,6 +35,8 @@ int xe_guc_upload(struct xe_guc *guc);
> >  int xe_guc_min_load_for_hwconfig(struct xe_guc *guc);
> >  int xe_guc_enable_communication(struct xe_guc *guc);
> >  int xe_guc_opt_in_features_enable(struct xe_guc *guc);
> > +void xe_guc_runtime_suspend(struct xe_guc *guc);
> > +void xe_guc_runtime_resume(struct xe_guc *guc);
> >  int xe_guc_suspend(struct xe_guc *guc);
> >  void xe_guc_notify(struct xe_guc *guc);
> >  int xe_guc_auth_huc(struct xe_guc *guc, u32 rsa_addr);
> > diff --git a/drivers/gpu/drm/xe/xe_guc_ct.c b/drivers/gpu/drm/xe/xe_guc_ct.c
> > index e68953ef3a00..a7b8d16d4041 100644
> > --- a/drivers/gpu/drm/xe/xe_guc_ct.c
> > +++ b/drivers/gpu/drm/xe/xe_guc_ct.c
> > @@ -634,6 +634,33 @@ void xe_guc_ct_stop(struct xe_guc_ct *ct)
> >  	stop_g2h_handler(ct);
> >  }
> >  
> > +/**
> > + * xe_guc_ct_runtime_suspend() - GuC CT runtime suspend
> > + * @ct: the &xe_guc_ct
> > + *
> > + * Set GuC CT to disabled state.
> > + */
> > +void xe_guc_ct_runtime_suspend(struct xe_guc_ct *ct)
> > +{
> > +	/*
> > +	 * Since we're already in runtime suspend path, we shouldn't have pending
> > +	 * messages. But if there happen to be any, we'd probably want them to be
> > +	 * thrown as errors for further investigation.
> > +	 */
> 
> What would also be helpful here is an assert the G2H credits are in a
> fully idle state too. We can do this in follow up if this has already
> merged.

Sorry, by credits do you mean to check g2h_outstanding?
IIUC guc_ct_change_state() already does it for us, or did I miss something?

Raag

> > +	xe_guc_ct_disable(ct);
> > +}
> > +
> > +/**
> > + * xe_guc_ct_runtime_resume() - GuC CT runtime resume
> > + * @ct: the &xe_guc_ct
> > + *
> > + * Restart GuC CT and set it to enabled state.
> > + */
> > +void xe_guc_ct_runtime_resume(struct xe_guc_ct *ct)
> > +{
> > +	xe_guc_ct_restart(ct);
> > +}
> > +
> >  static bool h2g_has_room(struct xe_guc_ct *ct, u32 cmd_len)
> >  {
> >  	struct guc_ctb *h2g = &ct->ctbs.h2g;
> > diff --git a/drivers/gpu/drm/xe/xe_guc_ct.h b/drivers/gpu/drm/xe/xe_guc_ct.h
> > index ca1ce2b3c354..5599939f8fe1 100644
> > --- a/drivers/gpu/drm/xe/xe_guc_ct.h
> > +++ b/drivers/gpu/drm/xe/xe_guc_ct.h
> > @@ -17,6 +17,8 @@ int xe_guc_ct_init_post_hwconfig(struct xe_guc_ct *ct);
> >  int xe_guc_ct_enable(struct xe_guc_ct *ct);
> >  int xe_guc_ct_restart(struct xe_guc_ct *ct);
> >  void xe_guc_ct_disable(struct xe_guc_ct *ct);
> > +void xe_guc_ct_runtime_resume(struct xe_guc_ct *ct);
> > +void xe_guc_ct_runtime_suspend(struct xe_guc_ct *ct);
> >  void xe_guc_ct_stop(struct xe_guc_ct *ct);
> >  void xe_guc_ct_flush_and_stop(struct xe_guc_ct *ct);
> >  void xe_guc_ct_fast_path(struct xe_guc_ct *ct);
> > diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
> > index 7b089e6fb63f..56e1351776c0 100644
> > --- a/drivers/gpu/drm/xe/xe_pm.c
> > +++ b/drivers/gpu/drm/xe/xe_pm.c
> > @@ -591,7 +591,7 @@ int xe_pm_runtime_suspend(struct xe_device *xe)
> >  	}
> >  
> >  	for_each_gt(gt, xe, id) {
> > -		err = xe_gt_suspend(gt);
> > +		err = xe->d3cold.allowed ? xe_gt_suspend(gt) : xe_gt_runtime_suspend(gt);
> >  		if (err)
> >  			goto out_resume;
> >  	}
> > @@ -633,10 +633,10 @@ int xe_pm_runtime_resume(struct xe_device *xe)
> >  
> >  	xe_rpm_lockmap_acquire(xe);
> >  
> > -	for_each_gt(gt, xe, id)
> > -		xe_gt_idle_disable_c6(gt);
> > -
> >  	if (xe->d3cold.allowed) {
> > +		for_each_gt(gt, xe, id)
> > +			xe_gt_idle_disable_c6(gt);
> > +
> >  		err = xe_pcode_ready(xe, true);
> >  		if (err)
> >  			goto out;
> > @@ -657,7 +657,7 @@ int xe_pm_runtime_resume(struct xe_device *xe)
> >  	xe_irq_resume(xe);
> >  
> >  	for_each_gt(gt, xe, id)
> > -		xe_gt_resume(gt);
> > +		xe->d3cold.allowed ? xe_gt_resume(gt) : xe_gt_runtime_resume(gt);
> >  
> >  	xe_display_pm_runtime_resume(xe);
> >  
> > diff --git a/drivers/gpu/drm/xe/xe_uc.c b/drivers/gpu/drm/xe/xe_uc.c
> > index 465bda355443..6a58b33248f5 100644
> > --- a/drivers/gpu/drm/xe/xe_uc.c
> > +++ b/drivers/gpu/drm/xe/xe_uc.c
> > @@ -301,6 +301,34 @@ int xe_uc_suspend(struct xe_uc *uc)
> >  	return xe_guc_suspend(&uc->guc);
> >  }
> >  
> > +/**
> > + * xe_uc_runtime_suspend() - UC runtime suspend
> > + * @uc: the UC object
> > + *
> > + * Runtime suspend all UCs.
> > + */
> > +void xe_uc_runtime_suspend(struct xe_uc *uc)
> > +{
> > +	if (!xe_device_uc_enabled(uc_to_xe(uc)))
> > +		return;
> > +
> > +	xe_guc_runtime_suspend(&uc->guc);
> > +}
> > +
> > +/**
> > + * xe_uc_runtime_resume() - UC runtime resume
> > + * @uc: the UC object
> > + *
> > + * Runtime resume all UCs.
> > + */
> > +void xe_uc_runtime_resume(struct xe_uc *uc)
> > +{
> > +	if (!xe_device_uc_enabled(uc_to_xe(uc)))
> > +		return;
> > +
> > +	xe_guc_runtime_resume(&uc->guc);
> > +}
> > +
> >  /**
> >   * xe_uc_declare_wedged() - Declare UC wedged
> >   * @uc: the UC object
> > diff --git a/drivers/gpu/drm/xe/xe_uc.h b/drivers/gpu/drm/xe/xe_uc.h
> > index 21c9306098cf..5398da1a8097 100644
> > --- a/drivers/gpu/drm/xe/xe_uc.h
> > +++ b/drivers/gpu/drm/xe/xe_uc.h
> > @@ -14,6 +14,8 @@ int xe_uc_init_post_hwconfig(struct xe_uc *uc);
> >  int xe_uc_load_hw(struct xe_uc *uc);
> >  void xe_uc_gucrc_disable(struct xe_uc *uc);
> >  int xe_uc_reset_prepare(struct xe_uc *uc);
> > +void xe_uc_runtime_resume(struct xe_uc *uc);
> > +void xe_uc_runtime_suspend(struct xe_uc *uc);
> >  void xe_uc_stop_prepare(struct xe_uc *uc);
> >  void xe_uc_stop(struct xe_uc *uc);
> >  int xe_uc_start(struct xe_uc *uc);
> > -- 
> > 2.34.1
> >