[PATCH v2] drm/xe: remove GuC reload in D3Hot path

Riana Tauro riana.tauro at intel.com
Mon Jun 24 10:50:53 UTC 2024


Hi Michal

On 6/24/2024 1:40 PM, Michal Wajdeczko wrote:
> Hi Riana,
> 
> 
> On 24.06.2024 09:27, Riana Tauro wrote:
>> Currently GuC is reloaded for both runtime suspend
>> and system suspend. For D3hot <-> D0 transitions
>> no power is lost on suspend and GuC reload is not
>> necessary.
> 
> quite aggressive line wrap at ~50, try wrap a ~72
> (only commit titles should be around ~50)

will wrap it at 72
> 
>>
>> remove GuC reload from D3Hot path and only enable/disable
>> CTB communications
> 
> "Remove .... communication."
will fix this
> 
>>
>> v2: rebase
>>
>> Signed-off-by: Riana Tauro <riana.tauro at intel.com>
>> ---
>>   drivers/gpu/drm/xe/xe_gt.c     | 19 ++++++++++---
>>   drivers/gpu/drm/xe/xe_gt.h     |  4 +--
>>   drivers/gpu/drm/xe/xe_guc.c    | 52 +++++++++++++++++++++++++++++++++-
>>   drivers/gpu/drm/xe/xe_guc.h    |  2 ++
>>   drivers/gpu/drm/xe/xe_guc_ct.c | 35 ++++++++++++++++++-----
>>   drivers/gpu/drm/xe/xe_guc_ct.h |  3 +-
>>   drivers/gpu/drm/xe/xe_pm.c     |  8 +++---
>>   drivers/gpu/drm/xe/xe_uc.c     | 30 ++++++++++++++++++++
>>   drivers/gpu/drm/xe/xe_uc.h     |  2 ++
>>   9 files changed, 136 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_gt.c b/drivers/gpu/drm/xe/xe_gt.c
>> index 759634cff1d8..5b48e4db9776 100644
>> --- a/drivers/gpu/drm/xe/xe_gt.c
>> +++ b/drivers/gpu/drm/xe/xe_gt.c
>> @@ -776,8 +776,9 @@ void xe_gt_suspend_prepare(struct xe_gt *gt)
>>   	XE_WARN_ON(xe_force_wake_put(gt_to_fw(gt), XE_FORCEWAKE_ALL));
>>   }
>>   
>> -int xe_gt_suspend(struct xe_gt *gt)
>> +int xe_gt_suspend(struct xe_gt *gt, bool runtime)
> 
> as you are changing function signature, please add full kernel-doc for
> this public function
will add the kernel-doc
> 
>>   {
>> +	struct xe_device *xe = gt_to_xe(gt);
>>   	int err;
>>   
>>   	xe_gt_dbg(gt, "suspending\n");
>> @@ -787,7 +788,11 @@ int xe_gt_suspend(struct xe_gt *gt)
>>   	if (err)
>>   		goto err_msg;
>>   
>> -	err = xe_uc_suspend(&gt->uc);
>> +	if (runtime && !xe->d3cold.allowed)
> 
> nit: maybe instead of just looking at some internal flag, it would be
> better to define helpers:
> 
> static inline bool xe_device_d3cold_allowed(xe) { .. }
> static inline bool xe_device_d3hot_allowed(xe) { .. }
This should be a different patch as multiple places currently
use this internal flag. Will send it out as a different patch.
> 
>> +		err = xe_uc_runtime_suspend(&gt->uc);
>> +	else
>> +		err = xe_uc_suspend(&gt->uc);
>> +
>>   	if (err)
>>   		goto err_force_wake;
>>   
>> @@ -825,8 +830,9 @@ int xe_gt_sanitize_freq(struct xe_gt *gt)
>>   	return ret;
>>   }
>>   
>> -int xe_gt_resume(struct xe_gt *gt)
>> +int xe_gt_resume(struct xe_gt *gt, bool runtime)
> 
> add kernel-doc
> 
>>   {
>> +	struct xe_device *xe = gt_to_xe(gt);
>>   	int err;
>>   
>>   	xe_gt_dbg(gt, "resuming\n");
>> @@ -834,7 +840,12 @@ int xe_gt_resume(struct xe_gt *gt)
>>   	if (err)
>>   		goto err_msg;
>>   
>> -	err = do_gt_restart(gt);
>> +	/* Do not reload GuC at runtime resume from D3Hot to D0 */
> 
> maybe better to explain "why" than "what":
> 
> /* GuC is still alive at D3hot, no need to reload it */
Sure will add this
> 
>> +	if (runtime && !xe->d3cold.allowed)
>> +		xe_uc_runtime_resume(&gt->uc);
>> +	else
>> +		err = do_gt_restart(gt);
>> +
>>   	if (err)
>>   		goto err_force_wake;
>>   
>> diff --git a/drivers/gpu/drm/xe/xe_gt.h b/drivers/gpu/drm/xe/xe_gt.h
>> index 1123fdfc4ebc..4c942e4716ad 100644
>> --- a/drivers/gpu/drm/xe/xe_gt.h
>> +++ b/drivers/gpu/drm/xe/xe_gt.h
>> @@ -52,8 +52,8 @@ int xe_gt_record_default_lrcs(struct xe_gt *gt);
>>   void xe_gt_record_user_engines(struct xe_gt *gt);
>>   
>>   void xe_gt_suspend_prepare(struct xe_gt *gt);
>> -int xe_gt_suspend(struct xe_gt *gt);
>> -int xe_gt_resume(struct xe_gt *gt);
>> +int xe_gt_suspend(struct xe_gt *gt, bool runtime);
>> +int xe_gt_resume(struct xe_gt *gt, bool runtime);
>>   void xe_gt_reset_async(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 172b65a50e31..1ea1d00f93f3 100644
>> --- a/drivers/gpu/drm/xe/xe_guc.c
>> +++ b/drivers/gpu/drm/xe/xe_guc.c
>> @@ -870,7 +870,7 @@ int xe_guc_enable_communication(struct xe_guc *guc)
>>   		guc_enable_irq(guc);
>>   	}
>>   
>> -	err = xe_guc_ct_enable(&guc->ct);
>> +	err = xe_guc_ct_register(&guc->ct);
>>   	if (err)
>>   		return err;
>>   
>> @@ -1101,6 +1101,56 @@ void xe_guc_sanitize(struct xe_guc *guc)
>>   	guc->submission_state.enabled = false;
>>   }
>>   
>> +/**
>> + * xe_guc_runtime_suspend - GuC runtime suspend
>> + * @guc: GuC object
>> + *
>> + * This function waits for any outstanding CTB
>> + * and disables CTB communication before entering
>> + * D3Hot
>> + *
>> + * Return: 0 on success, negative error code on error.
>> + */
>> +int xe_guc_runtime_suspend(struct xe_guc *guc)
>> +{
>> +	struct xe_guc_ct *ct = &guc->ct;
>> +
>> +	/*
>> +	 * Wait for any outstanding CTB before tearing down communication
>> +	 * with GuC.
>> +	 */
>> +	if (!wait_event_timeout(ct->wq, !ct->g2h_outstanding, (HZ / 5)))
>> +		return -ETIMEDOUT;
>> +
>> +	/* Disable CTB */
>> +	xe_guc_ct_disable(&guc->ct);
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>> + * xe_guc_runtime_resume - GuC runtime resume
>> + * @guc: GuC object
>> + *
>> + * This function enables CTB communication
>> + * and interrupts.
>> + */
>> +void xe_guc_runtime_resume(struct xe_guc *guc)
>> +{
>> +	/*
>> +	 * Power is not lost when resuming from D3Hot,
>> +	 * hence it is not necessary to reload GuC
>> +	 * everytime. Only enable interrupts and
>> +	 * CTB communication during resume
>> +	 */
>> +	guc_enable_irq(guc);
> 
> this will break VFs
> 
> can't you just use xe_guc_enable_communication() as it was ?

The intial series which was sent a while back had used 
enable_communication.Based on the review comment from Daniele it was 
changed to just setting enable/disable flag of CT

https://patchwork.freedesktop.org/patch/553801/?series=122772&rev=1

"Note that if we're not killing the GuC there isn't really a need to
unregister and re-register the CTBs, we could just set ct->enabled =
false on suspend and flip it back to ct->enabled = true on resume.

Daniele"

++Daniele

> it did the same steps what you are trying in this function
> 
>> +
>> +	xe_mmio_rmw32(guc_to_gt(guc), PMINTRMSK,
>> +		      ARAT_EXPIRED_INTRMSK, 0);
> 
> if power not lost we likely don't need this (as this is a default value
> and we already set it once as part of __xe_guc_upload()
This was removed in recent changes. Sorry missed this. Will remove it
> 
>> +
>> +	xe_guc_ct_enable(&guc->ct);
>> +}
>> +
>>   int xe_guc_reset_prepare(struct xe_guc *guc)
>>   {
>>   	return xe_guc_submit_reset_prepare(guc);
>> diff --git a/drivers/gpu/drm/xe/xe_guc.h b/drivers/gpu/drm/xe/xe_guc.h
>> index af59c9545753..a01999bb4a8e 100644
>> --- a/drivers/gpu/drm/xe/xe_guc.h
>> +++ b/drivers/gpu/drm/xe/xe_guc.h
>> @@ -22,6 +22,8 @@ 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_suspend(struct xe_guc *guc);
>> +int xe_guc_runtime_suspend(struct xe_guc *guc);
>> +void xe_guc_runtime_resume(struct xe_guc *guc);
>>   void xe_guc_notify(struct xe_guc *guc);
>>   int xe_guc_auth_huc(struct xe_guc *guc, u32 rsa_addr);
>>   int xe_guc_mmio_send(struct xe_guc *guc, const u32 *request, u32 len);
>> diff --git a/drivers/gpu/drm/xe/xe_guc_ct.c b/drivers/gpu/drm/xe/xe_guc_ct.c
>> index b4137fe195a4..400680c429fd 100644
>> --- a/drivers/gpu/drm/xe/xe_guc_ct.c
>> +++ b/drivers/gpu/drm/xe/xe_guc_ct.c
>> @@ -360,7 +360,16 @@ static void ct_exit_safe_mode(struct xe_guc_ct *ct)
>>   		xe_gt_dbg(ct_to_gt(ct), "GuC CT safe-mode disabled\n");
>>   }
>>   
>> -int xe_guc_ct_enable(struct xe_guc_ct *ct)
>> +/**
>> + * xe_guc_ct_register - register GuC CTB
>> + * @ct: GuC CT object
>> + *
>> + * register GuC CTB's and enable GuC CT
>> + * communication channel.
>> + *
>> + * Return: 0 on success, negative error code on error.
>> + */
>> +int xe_guc_ct_register(struct xe_guc_ct *ct)
> 
> hmm, can we have common naming convention across all driver components?
> 
> for the initialization there was pattern like:
> 
> 	- init_early
> 	- init
> 	- enable
> 	- disable
> 	- fini
> 
> and the "_register" suffix was mostly used by functions that registers
> the sysfs/debugfs attributes
> 
> now CTB is splitting 'enable' step into 'register' and 'enable' where
> the latter can't be used alone and be even more misleading

For the above comment, needed a way to split the registering of CTB and 
safe mode that is required during initialization which will not be 
needed on resume from D3hot.

ctb_init is already used.  I can use a bool variable runtime_suspend to 
differentiate between init and d3Hot if this split is not okay.
> 
> + Rodrigo
> 
>>   {
>>   	struct xe_device *xe = ct_to_xe(ct);
>>   	struct xe_gt *gt = ct_to_gt(ct);
>> @@ -383,11 +392,7 @@ int xe_guc_ct_enable(struct xe_guc_ct *ct)
>>   	if (err)
>>   		goto err_out;
>>   
>> -	xe_guc_ct_set_state(ct, XE_GUC_CT_STATE_ENABLED);
>> -
>> -	smp_mb();
>> -	wake_up_all(&ct->wq);
>> -	xe_gt_dbg(gt, "GuC CT communication channel enabled\n");
>> +	xe_guc_ct_enable(ct);
>>   
>>   	if (ct_needs_safe_mode(ct))
>>   		ct_enter_safe_mode(ct);
>> @@ -396,10 +401,26 @@ int xe_guc_ct_enable(struct xe_guc_ct *ct)
>>   
>>   err_out:
>>   	xe_gt_err(gt, "Failed to enable GuC CT (%pe)\n", ERR_PTR(err));
>> -
>>   	return err;
>>   }
>>   
>> +/**
>> + * xe_guc_ct_enable - Set GuC CT to enabled state
>> + * @ct: GuC CT object
>> + *
>> + * Set GuC CT to enabled state
>> + */
>> +void xe_guc_ct_enable(struct xe_guc_ct *ct)
>> +{
>> +	struct xe_gt *gt = ct_to_gt(ct);
>> +
>> +	xe_guc_ct_set_state(ct, XE_GUC_CT_STATE_ENABLED);
>> +
>> +	smp_mb();
>> +	wake_up_all(&ct->wq);
>> +	xe_gt_dbg(gt, "GuC CT communication channel enabled\n");
> 
> this seems wrong, as CTB was enabled and fully functional once you
> called guc_ct_control_toggle(true), decoupling reporting of what have
> already happened in the previous steps is IMO just misleading

all the guc_ct_send_* & g2h_read functions check this state. So 
shouldn't the log be after the state has changed to enable.
> 
> + Matt
> 
>> +}
>> +
>>   static void stop_g2h_handler(struct xe_guc_ct *ct)
>>   {
>>   	cancel_work_sync(&ct->g2h_worker);
>> diff --git a/drivers/gpu/drm/xe/xe_guc_ct.h b/drivers/gpu/drm/xe/xe_guc_ct.h
>> index 105bb8e99a8d..f786b3ec2b68 100644
>> --- a/drivers/gpu/drm/xe/xe_guc_ct.h
>> +++ b/drivers/gpu/drm/xe/xe_guc_ct.h
>> @@ -11,7 +11,8 @@
>>   struct drm_printer;
>>   
>>   int xe_guc_ct_init(struct xe_guc_ct *ct);
>> -int xe_guc_ct_enable(struct xe_guc_ct *ct);
>> +int xe_guc_ct_register(struct xe_guc_ct *ct);
>> +void xe_guc_ct_enable(struct xe_guc_ct *ct);
>>   void xe_guc_ct_disable(struct xe_guc_ct *ct);
>>   void xe_guc_ct_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 de3b5df65e48..070d28d193c7 100644
>> --- a/drivers/gpu/drm/xe/xe_pm.c
>> +++ b/drivers/gpu/drm/xe/xe_pm.c
>> @@ -99,7 +99,7 @@ int xe_pm_suspend(struct xe_device *xe)
>>   	xe_display_pm_suspend(xe, false);
>>   
>>   	for_each_gt(gt, xe, id) {
>> -		err = xe_gt_suspend(gt);
>> +		err = xe_gt_suspend(gt, false);
>>   		if (err) {
>>   			xe_display_pm_resume(xe, false);
>>   			goto err;
>> @@ -154,7 +154,7 @@ int xe_pm_resume(struct xe_device *xe)
>>   	xe_display_pm_resume(xe, false);
>>   
>>   	for_each_gt(gt, xe, id)
>> -		xe_gt_resume(gt);
>> +		xe_gt_resume(gt, false);
>>   
>>   	err = xe_bo_restore_user(xe);
>>   	if (err)
>> @@ -370,7 +370,7 @@ int xe_pm_runtime_suspend(struct xe_device *xe)
>>   	}
>>   
>>   	for_each_gt(gt, xe, id) {
>> -		err = xe_gt_suspend(gt);
>> +		err = xe_gt_suspend(gt, true);
>>   		if (err)
>>   			goto out;
>>   	}
>> @@ -423,7 +423,7 @@ int xe_pm_runtime_resume(struct xe_device *xe)
>>   	xe_irq_resume(xe);
>>   
>>   	for_each_gt(gt, xe, id)
>> -		xe_gt_resume(gt);
>> +		xe_gt_resume(gt, true);
>>   
>>   	if (xe->d3cold.allowed) {
>>   		xe_display_pm_resume(xe, true);
>> diff --git a/drivers/gpu/drm/xe/xe_uc.c b/drivers/gpu/drm/xe/xe_uc.c
>> index 0f240534fb72..997ab4e82931 100644
>> --- a/drivers/gpu/drm/xe/xe_uc.c
>> +++ b/drivers/gpu/drm/xe/xe_uc.c
>> @@ -288,6 +288,36 @@ int xe_uc_suspend(struct xe_uc *uc)
>>   	return xe_guc_suspend(&uc->guc);
>>   }
>>   
>> +/**
>> + * xe_uc_runtime_suspend - uC runtime suspend
>> + * @uc: uC object
>> + *
>> + * Return: 0 on success, negative error code on error.
>> + */
>> +int xe_uc_runtime_suspend(struct xe_uc *uc)
>> +{
>> +	/* GuC submission not enabled, nothing to do */
> 
> nit: this comment doesn't bring too much new info and likely can be
> dropped without losing any clarity of the code

sure will drop it

Thanks
Riana
> 
>> +	if (!xe_device_uc_enabled(uc_to_xe(uc)))
>> +		return 0;
>> +
>> +	return xe_guc_runtime_suspend(&uc->guc);
>> +}
>> +
>> +/**
>> + * xe_uc_runtime_resume - uC runtime resume
>> + * @uc: uC object
>> + *
>> + * Called while resuming from D3Hot
>> + */
>> +void xe_uc_runtime_resume(struct xe_uc *uc)
>> +{
>> +	/* GuC submission not enabled, nothing to do */
>> +	if (!xe_device_uc_enabled(uc_to_xe(uc)))
>> +		return;
>> +
>> +	xe_guc_runtime_resume(&uc->guc);
>> +}
>> +
>>   /**
>>    * xe_uc_remove() - Clean up the UC structures before driver removal
>>    * @uc: the UC object
>> diff --git a/drivers/gpu/drm/xe/xe_uc.h b/drivers/gpu/drm/xe/xe_uc.h
>> index 11856f24e6f9..dd483ea43b9b 100644
>> --- a/drivers/gpu/drm/xe/xe_uc.h
>> +++ b/drivers/gpu/drm/xe/xe_uc.h
>> @@ -15,6 +15,8 @@ int xe_uc_init_hw(struct xe_uc *uc);
>>   int xe_uc_fini_hw(struct xe_uc *uc);
>>   void xe_uc_gucrc_disable(struct xe_uc *uc);
>>   int xe_uc_reset_prepare(struct xe_uc *uc);
>> +int xe_uc_runtime_suspend(struct xe_uc *uc);
>> +void xe_uc_runtime_resume(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);


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