Re: [PATCH 03/15] drm/i915/guc/slpc: Gate Host RPS when SLPC is enabled

On 7/27/2021 3:44 PM, Matthew Brost wrote:

On Mon, Jul 26, 2021 at 12:07:48PM -0700, Vinay Belgaumkar wrote:

...

Also ensure uc_init is called before we initialize RPS so that we can check for SLPC support. We do not need to enable up/down interrupts when SLPC is enabled. However, we still need the ARAT interrupt, which will be enabled separately later.

Do we not need a check for rps_uses_slpc in intel_rps_enable? I guessing there is a reason why we don't but can't seem to figure that out.

Yeah, it's due to this check in there - if (rps->max_freq <= rps->min_freq) /* leave disabled, no room for dynamic reclocking */;

With slpc, rps->max_freq and rps->min freq remain uninitialized, so the if condition just falls through and returns with this- if (!enabled) return;

Thanks, Vinay.

Matt

...

Signed-off-by: Vinay Belgaumkar vinay.belgaumkar@intel.com Signed-off-by: Sundaresan Sujaritha sujaritha.sundaresan@intel.com

---

drivers/gpu/drm/i915/gt/intel_gt.c | 2 +- drivers/gpu/drm/i915/gt/intel_rps.c | 20 ++++++++++++++++++++ 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c index a64aa43f7cd9..04dd69bcf6cb 100644 --- a/drivers/gpu/drm/i915/gt/intel_gt.c +++ b/drivers/gpu/drm/i915/gt/intel_gt.c @@ -41,8 +41,8 @@ void intel_gt_init_early(struct intel_gt *gt, struct drm_i915_private *i915) intel_gt_init_timelines(gt); intel_gt_pm_init_early(gt);

• intel_rps_init_early(&gt->rps); intel_uc_init_early(&gt->uc);

• intel_rps_init_early(&gt->rps); }

  int intel_gt_probe_lmem(struct intel_gt *gt)

diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c b/drivers/gpu/drm/i915/gt/intel_rps.c index 0c8e7f2b06f0..e858eeb2c59d 100644 --- a/drivers/gpu/drm/i915/gt/intel_rps.c +++ b/drivers/gpu/drm/i915/gt/intel_rps.c @@ -37,6 +37,13 @@ static struct intel_uncore *rps_to_uncore(struct intel_rps *rps) return rps_to_gt(rps)->uncore; }

+static bool rps_uses_slpc(struct intel_rps *rps) +{

• struct intel_gt *gt = rps_to_gt(rps);
• return intel_uc_uses_guc_slpc(&gt->uc);

+}

• static u32 rps_pm_sanitize_mask(struct intel_rps *rps, u32 mask) { return mask & ~rps->pm_intrmsk_mbz;

@@ -167,6 +174,8 @@ static void rps_enable_interrupts(struct intel_rps *rps) { struct intel_gt *gt = rps_to_gt(rps);

• GEM_BUG_ON(rps_uses_slpc(rps));
• GT_TRACE(gt, "interrupts:on rps->pm_events: %x, rps_pm_mask:%x\n", rps->pm_events, rps_pm_mask(rps, rps->last_freq));

@@ -771,6 +780,8 @@ static int gen6_rps_set(struct intel_rps *rps, u8 val) struct drm_i915_private *i915 = rps_to_i915(rps); u32 swreq;

• GEM_BUG_ON(rps_uses_slpc(rps));
• if (GRAPHICS_VER(i915) >= 9) swreq = GEN9_FREQUENCY(val); else if (IS_HASWELL(i915) || IS_BROADWELL(i915))

@@ -861,6 +872,9 @@ void intel_rps_park(struct intel_rps *rps) { int adj;

• if (!intel_rps_is_enabled(rps))

• return;
  

• GEM_BUG_ON(atomic_read(&rps->num_waiters));

  if (!intel_rps_clear_active(rps))

@@ -1829,6 +1843,9 @@ void intel_rps_init(struct intel_rps *rps) { struct drm_i915_private *i915 = rps_to_i915(rps);

• if (rps_uses_slpc(rps))

• return;
  

• if (IS_CHERRYVIEW(i915)) chv_rps_init(rps); else if (IS_VALLEYVIEW(i915))

@@ -1885,6 +1902,9 @@ void intel_rps_init(struct intel_rps *rps)

void intel_rps_sanitize(struct intel_rps *rps) {

• if (rps_uses_slpc(rps))

• return;
  

• if (GRAPHICS_VER(rps_to_i915(rps)) >= 6) rps_disable_interrupts(rps); }

-- 2.25.0