Intel-GFX Archive on lore.kernel.org
 help / color / mirror / Atom feed
From: Anshuman Gupta <anshuman.gupta@intel.com>
To: intel-gfx@lists.freedesktop.org
Cc: rodrigo.vivi@intel.com
Subject: [Intel-gfx] [PATCH] drm/i915/selftest: Fix gt_pm live_gt_clocks test
Date: Mon, 31 Oct 2022 17:24:52 +0530	[thread overview]
Message-ID: <20221031115452.1813981-1-anshuman.gupta@intel.com> (raw)

While reading the engine timestamps there can be uncontrollable
concurrent mmio access via other i915 child drivers and by GuC,
which may cause mmio latency to read the engine timestamps,
Account such latency to calculate time to read engine timestamp.

Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
---
 drivers/gpu/drm/i915/gt/selftest_gt_pm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/selftest_gt_pm.c b/drivers/gpu/drm/i915/gt/selftest_gt_pm.c
index be94f863bdef..4f299590ae62 100644
--- a/drivers/gpu/drm/i915/gt/selftest_gt_pm.c
+++ b/drivers/gpu/drm/i915/gt/selftest_gt_pm.c
@@ -50,8 +50,8 @@ static void measure_clocks(struct intel_engine_cs *engine,
 
 		udelay(1000);
 
-		dt[i] = ktime_sub(ktime_get(), dt[i]);
 		cycles[i] += ENGINE_READ_FW(engine, RING_TIMESTAMP);
+		dt[i] = ktime_sub(ktime_get(), dt[i]);
 		local_irq_enable();
 	}
 
-- 
2.25.1


             reply	other threads:[~2022-10-31 11:55 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-31 11:54 Anshuman Gupta [this message]
2022-10-31 19:27 ` [Intel-gfx] ✗ Fi.CI.BAT: failure for drm/i915/selftest: Fix gt_pm live_gt_clocks test Patchwork

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20221031115452.1813981-1-anshuman.gupta@intel.com \
    --to=anshuman.gupta@intel.com \
    --cc=intel-gfx@lists.freedesktop.org \
    --cc=rodrigo.vivi@intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox