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

Matthew Brost
2021-07-27T15:41:42Z

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@intel.com>
> ---
> 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@intel.com>

> + * 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