drm/i915/selftest: Add throttle reason diagnostics to RPS selftests

Report GPU throttle reasons when RPS tests fail to reach expected
frequencies or power levels.

v2: Read the throttle value before the spinner ends (Raag)
    Add a condition before printing throttle value (Krzysztof)
v3: Extend throttle reasons debug support (Raag)
v4: Cosmetic changes (Raag)

Signed-off-by: Sk Anirban <sk.anirban@intel.com>
Reviewed-by: Raag Jadav <raag.jadav@intel.com>
Reviewed-by: Krzysztof Karas <krzysztof.karas@intel.com>
Link: https://patch.msgid.link/20251223101605.3304379-2-sk.anirban@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>

diff --git a/drivers/gpu/drm/i915/gt/selftest_rps.c b/drivers/gpu/drm/i915/gt/selftest_rps.c
index 73bc91c6ea075c9045c1affef32bfe1ea77c0f57..be77fba2ec4920dc74a68adba279fd783593b60a 100644 (file)
--- a/drivers/gpu/drm/i915/gt/selftest_rps.c
+++ b/drivers/gpu/drm/i915/gt/selftest_rps.c
@@ -378,6 +378,7 @@ int live_rps_control(void *arg)
        enum intel_engine_id id;
        struct igt_spinner spin;
        intel_wakeref_t wakeref;
+       u32 throttle;
        int err = 0;
 
        /*
@@ -463,6 +464,9 @@ int live_rps_control(void *arg)
                max = rps_set_check(rps, limit);
                max_dt = ktime_sub(ktime_get(), max_dt);
 
+               throttle = intel_uncore_read(gt->uncore, intel_gt_perf_limit_reasons_reg(gt));
+               throttle &= GT0_PERF_LIMIT_REASONS_MASK;
+
                min_dt = ktime_get();
                min = rps_set_check(rps, rps->min_freq);
                min_dt = ktime_sub(ktime_get(), min_dt);
@@ -478,11 +482,9 @@ int live_rps_control(void *arg)
                        min, max, ktime_to_ns(min_dt), ktime_to_ns(max_dt));
 
                if (limit != rps->max_freq) {
-                       u32 throttle = intel_uncore_read(gt->uncore,
-                                                        intel_gt_perf_limit_reasons_reg(gt));
-
-                       pr_warn("%s: GPU throttled with reasons 0x%08x\n",
-                               engine->name, throttle & GT0_PERF_LIMIT_REASONS_MASK);
+                       if (throttle)
+                               pr_warn("%s: GPU throttled with reasons 0x%08x\n",
+                                       engine->name, throttle);
                        show_pstate_limits(rps);
                }
 
@@ -1138,6 +1140,7 @@ int live_rps_power(void *arg)
        struct intel_engine_cs *engine;
        enum intel_engine_id id;
        struct igt_spinner spin;
+       u32 throttle;
        int err = 0;
 
        /*
@@ -1195,6 +1198,9 @@ int live_rps_power(void *arg)
                max.freq = rps->max_freq;
                max.power = measure_power_at(rps, &max.freq);
 
+               throttle = intel_uncore_read(gt->uncore, intel_gt_perf_limit_reasons_reg(gt));
+               throttle &= GT0_PERF_LIMIT_REASONS_MASK;
+
                min.freq = rps->min_freq;
                min.power = measure_power_at(rps, &min.freq);
 
@@ -1210,12 +1216,21 @@ int live_rps_power(void *arg)
                        pr_notice("Could not control frequency, ran at [%d:%uMHz, %d:%uMhz]\n",
                                  min.freq, intel_gpu_freq(rps, min.freq),
                                  max.freq, intel_gpu_freq(rps, max.freq));
+
+                       if (throttle)
+                               pr_warn("%s: GPU throttled with reasons 0x%08x\n",
+                                       engine->name, throttle);
                        continue;
                }
 
                if (11 * min.power > 10 * max.power) {
                        pr_err("%s: did not conserve power when setting lower frequency!\n",
                               engine->name);
+
+                       if (throttle)
+                               pr_warn("%s: GPU throttled with reasons 0x%08x\n",
+                                       engine->name, throttle);
+
                        err = -EINVAL;
                        break;
                }
@@ -1241,6 +1256,7 @@ int live_rps_dynamic(void *arg)
        struct intel_engine_cs *engine;
        enum intel_engine_id id;
        struct igt_spinner spin;
+       u32 throttle;
        int err = 0;
 
        /*
@@ -1293,6 +1309,9 @@ int live_rps_dynamic(void *arg)
                max.freq = wait_for_freq(rps, rps->max_freq, 500);
                max.dt = ktime_sub(ktime_get(), max.dt);
 
+               throttle = intel_uncore_read(gt->uncore, intel_gt_perf_limit_reasons_reg(gt));
+               throttle &= GT0_PERF_LIMIT_REASONS_MASK;
+
                igt_spinner_end(&spin);
 
                min.dt = ktime_get();
@@ -1308,6 +1327,11 @@ int live_rps_dynamic(void *arg)
                if (min.freq >= max.freq) {
                        pr_err("%s: dynamic reclocking of spinner failed\n!",
                               engine->name);
+
+                       if (throttle)
+                               pr_warn("%s: GPU throttled with reasons 0x%08x\n",
+                                       engine->name, throttle);
+
                        err = -EINVAL;
                }