From patchwork Fri Apr 20 13:45:49 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Mika Kuoppala X-Patchwork-Id: 10353047 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id BDA8D60365 for ; Fri, 20 Apr 2018 15:50:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AEAE228711 for ; Fri, 20 Apr 2018 15:50:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A3855287BE; Fri, 20 Apr 2018 15:50:31 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 3BE2528711 for ; Fri, 20 Apr 2018 15:50:31 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id BC24D6EB10; Fri, 20 Apr 2018 15:47:59 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by gabe.freedesktop.org (Postfix) with ESMTPS id 9468A6E06A for ; Fri, 20 Apr 2018 13:46:33 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Apr 2018 06:46:29 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,301,1520924400"; d="scan'208";a="52323774" Received: from rosetta.fi.intel.com ([10.237.72.186]) by orsmga002.jf.intel.com with ESMTP; 20 Apr 2018 06:46:27 -0700 Received: by rosetta.fi.intel.com (Postfix, from userid 1000) id 5E612840755; Fri, 20 Apr 2018 16:45:52 +0300 (EEST) From: Mika Kuoppala To: intel-gfx@lists.freedesktop.org Date: Fri, 20 Apr 2018 16:45:49 +0300 Message-Id: <20180420134550.17590-1-mika.kuoppala@linux.intel.com> X-Mailer: git-send-email 2.14.1 MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 1/2] drm/i915: Use ktime on wait_for X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: stable@vger.kernel.org Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP We use jiffies to determine when wait expires. However Imre did find out that jiffies can and will do a >1 increments on certain situations [1]. When this happens in a wait_for loop, we return timeout errorneously much earlier than what the real wallclock would say. We can't afford our waits to timeout prematurely. Discard jiffies and change to ktime to detect timeouts. v2: added bugzilla entry (Imre), added stable (Chris) Reported-by: Imre Deak References: https://lkml.org/lkml/2018/4/18/798 [1] Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105771 Cc: Imre Deak Cc: Chris Wilson Cc: Ville Syrjälä Cc: Signed-off-by: Mika Kuoppala Reviewed-by: Chris Wilson --- drivers/gpu/drm/i915/intel_drv.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h index 8b20824e806e..ac7565220aa3 100644 --- a/drivers/gpu/drm/i915/intel_drv.h +++ b/drivers/gpu/drm/i915/intel_drv.h @@ -49,12 +49,12 @@ * check the condition before the timeout. */ #define __wait_for(OP, COND, US, Wmin, Wmax) ({ \ - unsigned long timeout__ = jiffies + usecs_to_jiffies(US) + 1; \ + const ktime_t end__ = ktime_add_ns(ktime_get_raw(), 1000ll * (US)); \ long wait__ = (Wmin); /* recommended min for usleep is 10 us */ \ int ret__; \ might_sleep(); \ for (;;) { \ - bool expired__ = time_after(jiffies, timeout__); \ + const bool expired__ = ktime_after(ktime_get_raw(), end__); \ OP; \ if (COND) { \ ret__ = 0; \