Re: [PATCH 11/15] drm/i915/guc/slpc: Enable ARAT timer interrupt

["Belgaumkar, Vinay" <vinay.belgaumkar@xxxxxxxxx>]

On 7/27/2021 8:40 AM, Matthew Brost wrote:
> On Mon, Jul 26, 2021 at 12:07:56PM -0700, Vinay Belgaumkar wrote:
> > This interrupt is enabled during RPS initialization, and
> > now needs to be done by SLPC code. It allows ARAT timer
> > expiry interrupts to get forwarded to GuC.
> >
> > Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@xxxxxxxxx>
> > ---
> >   drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c | 16 ++++++++++++++++
> >   drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h |  2 ++
> >   drivers/gpu/drm/i915/gt/uc/intel_uc.c       |  8 ++++++++
> >   3 files changed, 26 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
> > index 995d3d4807a3..c79dba60b2e6 100644
> > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
> > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
> > @@ -392,6 +392,20 @@ int intel_guc_slpc_get_min_freq(struct intel_guc_slpc *slpc, u32 *val)
> >   	return ret;
> >   }
> >   
> > +void intel_guc_pm_intrmsk_enable(struct intel_gt *gt)
> > +{
> > +	u32 pm_intrmsk_mbz = 0;
> > +
> > +	/* Allow GuC to receive ARAT timer expiry event.
>
> I've been berated for using comments like this this by other engineers.
> I personally don't care at all (nor does checkpatch) but if you want to
> avoid the wrath of others I'd change this to what I have below:
>
> /*
>   * Allow GuC to receive ARAT timer expiry event.
>   * This interrupt register is setup by RPS code
>   * when host based Turbo is enabled.
>   */
>
> Same goes for comment below of same style.
>
> Either way, patch looks good to me. With that:
> Reviewed-by: Matthew Brost <matthew.brost@xxxxxxxxx>

Fixed.
Thanks,
Vinay.
> > +	 * This interrupt register is setup by RPS code
> > +	 * when host based Turbo is enabled.
> > +	 */
> > +	pm_intrmsk_mbz |= ARAT_EXPIRED_INTRMSK;
> > +
> > +	intel_uncore_rmw(gt->uncore,
> > +			   GEN6_PMINTRMSK, pm_intrmsk_mbz, 0);
> > +}
> > +
> >   /*
> >    * intel_guc_slpc_enable() - Start SLPC
> >    * @slpc: pointer to intel_guc_slpc.
> > @@ -439,6 +453,8 @@ int intel_guc_slpc_enable(struct intel_guc_slpc *slpc)
> >   
> >   	slpc_query_task_state(slpc);
> >   
> > +	intel_guc_pm_intrmsk_enable(&i915->gt);
> > +
> >   	/* min and max frequency limits being used by SLPC */
> >   	drm_info(&i915->drm, "SLPC min freq: %u Mhz, max is %u Mhz\n",
> >   			slpc_decode_min_freq(slpc),
> > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h
> > index d133c8020c16..f128143cc1d8 100644
> > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h
> > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h
> > @@ -9,6 +9,7 @@
> >   #include "intel_guc_submission.h"
> >   #include "intel_guc_slpc_types.h"
> >   
> > +struct intel_gt;
> >   struct drm_printer;
> >   
> >   static inline bool intel_guc_slpc_is_supported(struct intel_guc *guc)
> > @@ -35,5 +36,6 @@ int intel_guc_slpc_set_min_freq(struct intel_guc_slpc *slpc, u32 val);
> >   int intel_guc_slpc_get_max_freq(struct intel_guc_slpc *slpc, u32 *val);
> >   int intel_guc_slpc_get_min_freq(struct intel_guc_slpc *slpc, u32 *val);
> >   int intel_guc_slpc_info(struct intel_guc_slpc *slpc, struct drm_printer *p);
> > +void intel_guc_pm_intrmsk_enable(struct intel_gt *gt);
> >   
> >   #endif
> > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.c b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> > index b98c14f8c229..9238bc076605 100644
> > --- a/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> > +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> > @@ -652,6 +652,7 @@ void intel_uc_suspend(struct intel_uc *uc)
> >   static int __uc_resume(struct intel_uc *uc, bool enable_communication)
> >   {
> >   	struct intel_guc *guc = &uc->guc;
> > +	struct intel_gt *gt = guc_to_gt(guc);
> >   	int err;
> >   
> >   	if (!intel_guc_is_fw_running(guc))
> > @@ -663,6 +664,13 @@ static int __uc_resume(struct intel_uc *uc, bool enable_communication)
> >   	if (enable_communication)
> >   		guc_enable_communication(guc);
> >   
> > +	/* If we are only resuming GuC communication but not reloading
> > +	 * GuC, we need to ensure the ARAT timer interrupt is enabled
> > +	 * again. In case of GuC reload, it is enabled during SLPC enable.
> > +	 */
> > +	if (enable_communication && intel_uc_uses_guc_slpc(uc))
> > +		intel_guc_pm_intrmsk_enable(gt);
> > +
> >   	err = intel_guc_resume(guc);
> >   	if (err) {
> >   		DRM_DEBUG_DRIVER("Failed to resume GuC, err=%d", err);
> > --
> > 2.25.0