From 2ebc9e4af0291d2e8d14ecc0bad8f36de8cc6e62 Mon Sep 17 00:00:00 2001 From: Anshuman Gupta Date: Tue, 30 Nov 2021 18:50:05 +0530 Subject: [PATCH] drm/i915/selftest: Disable IRQ for timestamp calculation gt_pm selftest calculates engine ticks cycles and wall time cycles by delta of respective engine elapsed TIMESTAMP and ktime for period of 1000us. It compares the engine ticks cycles with wall time cycles. Disable local cpu interrupt so that interrupt handler does not switch out the thread during measure_clocks() and prevent miscalculation of engine tick cycles. v2: - nuke preempt_{disable,enable}, as disable_local_irq() disable the preemption. (Chris) Cc: Chris P Wilson Cc: Badal Nilawar Cc: Ashutosh Dixit Signed-off-by: Anshuman Gupta Reviewed-by: Ashutosh Dixit Link: https://patchwork.freedesktop.org/patch/msgid/20211130132005.6305-1-anshuman.gupta@intel.com --- drivers/gpu/drm/i915/gt/selftest_gt_pm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/selftest_gt_pm.c b/drivers/gpu/drm/i915/gt/selftest_gt_pm.c index b944121..55c5cdb 100644 --- a/drivers/gpu/drm/i915/gt/selftest_gt_pm.c +++ b/drivers/gpu/drm/i915/gt/selftest_gt_pm.c @@ -43,7 +43,7 @@ static void measure_clocks(struct intel_engine_cs *engine, int i; for (i = 0; i < 5; i++) { - preempt_disable(); + local_irq_disable(); cycles[i] = -ENGINE_READ_FW(engine, RING_TIMESTAMP); dt[i] = ktime_get(); @@ -51,7 +51,7 @@ static void measure_clocks(struct intel_engine_cs *engine, dt[i] = ktime_sub(ktime_get(), dt[i]); cycles[i] += ENGINE_READ_FW(engine, RING_TIMESTAMP); - preempt_enable(); + local_irq_enable(); } /* Use the median of both cycle/dt; close enough */ -- 2.7.4