drm/i915/selftests: Skip energy consumption tests if not controlling freq

If we can not manipulate the frequency with RPS, then comparing min/max
power consumption is pointless / misleading. We will leave the warning
about not being able to control the frequency selection via RPS to other
tests so as not to confuse this more specialised check.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200420172739.11620-2-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/gt/selftest_rps.c b/drivers/gpu/drm/i915/gt/selftest_rps.c
index b1a435db1edcee50ded0baa12023f346a5f47190..149a3de86cb92206bd756cb6105e6b1cf10b93a0 100644 (file)
--- a/drivers/gpu/drm/i915/gt/selftest_rps.c
+++ b/drivers/gpu/drm/i915/gt/selftest_rps.c
@@ -485,26 +485,21 @@ static u64 __measure_power(int duration_ms)
        return div64_u64(1000 * 1000 * dE, dt);
 }
 
-static u64 measure_power_at(struct intel_rps *rps, int freq)
+static u64 measure_power_at(struct intel_rps *rps, int *freq)
 {
        u64 x[5];
        int i;
 
        mutex_lock(&rps->lock);
        GEM_BUG_ON(!rps->active);
-       intel_rps_set(rps, freq);
+       intel_rps_set(rps, *freq);
        mutex_unlock(&rps->lock);
 
        msleep(20); /* more than enough time to stabilise! */
 
-       i = read_cagf(rps);
-       if (i != freq)
-               pr_notice("Running at %x [%uMHz], not target %x [%uMHz]\n",
-                         i, intel_gpu_freq(rps, i),
-                         freq, intel_gpu_freq(rps, freq));
-
        for (i = 0; i < 5; i++)
                x[i] = __measure_power(5);
+       *freq = read_cagf(rps);
 
        /* A simple triangle filter for better result stability */
        sort(x, 5, sizeof(*x), cmp_u64, NULL);
@@ -542,7 +537,10 @@ int live_rps_power(void *arg)
 
        for_each_engine(engine, gt, id) {
                struct i915_request *rq;
-               u64 min, max;
+               struct {
+                       u64 power;
+                       int freq;
+               } min, max;
 
                if (!intel_engine_can_store_dword(engine))
                        continue;
@@ -565,16 +563,27 @@ int live_rps_power(void *arg)
                        break;
                }
 
-               max = measure_power_at(rps, rps->max_freq);
-               min = measure_power_at(rps, rps->min_freq);
+               max.freq = rps->max_freq;
+               max.power = measure_power_at(rps, &max.freq);
+
+               min.freq = rps->min_freq;
+               min.power = measure_power_at(rps, &min.freq);
 
                igt_spinner_end(&spin);
 
                pr_info("%s: min:%llumW @ %uMHz, max:%llumW @ %uMHz\n",
                        engine->name,
-                       min, intel_gpu_freq(rps, rps->min_freq),
-                       max, intel_gpu_freq(rps, rps->max_freq));
-               if (11 * min > 10 * max) {
+                       min.power, intel_gpu_freq(rps, min.freq),
+                       max.power, intel_gpu_freq(rps, max.freq));
+
+               if (10 * min.freq >= 9 * max.freq) {
+                       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));
+                       continue;
+               }
+
+               if (11 * min.power > 10 * max.power) {
                        pr_err("%s: did not conserve power when setting lower frequency!\n",
                               engine->name);
                        err = -EINVAL;