From patchwork Fri Jun 23 07:53:40 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 9805897 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 1C9F9600C5 for ; Fri, 23 Jun 2017 07:53:59 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 11456286EB for ; Fri, 23 Jun 2017 07:53:59 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 05D7D28722; Fri, 23 Jun 2017 07:53:59 +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=-4.2 required=2.0 tests=BAYES_00, 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 8BBC3286EB for ; Fri, 23 Jun 2017 07:53:58 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6338D6E74F; Fri, 23 Jun 2017 07:53:54 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by gabe.freedesktop.org (Postfix) with ESMTPS id 19DAC6E74F; Fri, 23 Jun 2017 07:53:53 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8324A80465; Fri, 23 Jun 2017 07:53:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 8324A80465 Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=hdegoede@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 8324A80465 Received: from shalem.localdomain.com (ovpn-117-52.ams2.redhat.com [10.36.117.52]) by smtp.corp.redhat.com (Postfix) with ESMTP id D09245C894; Fri, 23 Jun 2017 07:53:50 +0000 (UTC) From: Hans de Goede To: Daniel Vetter , Jani Nikula , =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= , Imre Deak Subject: [PATCH 2nd resend 4/4] drm/i915: Acquire PUNIT->PMIC bus for intel_uncore_forcewake_reset() Date: Fri, 23 Jun 2017 09:53:40 +0200 Message-Id: <20170623075340.7072-5-hdegoede@redhat.com> In-Reply-To: <20170623075340.7072-1-hdegoede@redhat.com> References: <20170623075340.7072-1-hdegoede@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Fri, 23 Jun 2017 07:53:52 +0000 (UTC) Cc: Hans de Goede , intel-gfx , dri-devel@lists.freedesktop.org X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP intel_uncore_forcewake_reset() does forcewake puts and gets as such we need to make sure that no-one tries to access the PUNIT->PMIC bus (on systems where this bus is shared) while it runs, otherwise bad things happen. Normally this is taken care of by the i915_pmic_bus_access_notifier() which does an intel_uncore_forcewake_get(FORCEWAKE_ALL) when some other driver tries to access the PMIC bus, so that later forcewake gets are no-ops (for the duration of the bus access). But intel_uncore_forcewake_reset gets called in 3 cases: 1) Before registering the pmic_bus_access_notifier 2) After unregistering the pmic_bus_access_notifier 3) To reset forcewake state on a GPU reset In all 3 cases the i915_pmic_bus_access_notifier() protection is insufficient. This commit fixes the pmic bus access race this causes by making intel_uncore_forcewake_reset() call iosf_mbi_punit_acquire() (and iosf_mbi_punit_release() when done). Note that iosf_mbi_punit_acquire() locks a mutex and thus intel_uncore_forcewake_reset() may sleep after this commit. I've checked all callers and they all already take other mutexes, so this is not a problem. Signed-off-by: Hans de Goede --- drivers/gpu/drm/i915/intel_uncore.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c index 882cf7187a57..0fb829cc1cbd 100644 --- a/drivers/gpu/drm/i915/intel_uncore.c +++ b/drivers/gpu/drm/i915/intel_uncore.c @@ -252,6 +252,9 @@ static void intel_uncore_forcewake_reset(struct drm_i915_private *dev_priv, int retry_count = 100; enum forcewake_domains fw, active_domains; + /* Acquire the PUNIT->PMIC bus before modifying forcewake settings */ + iosf_mbi_punit_acquire(); + /* Hold uncore.lock across reset to prevent any register access * with forcewake not set correctly. Wait until all pending * timers are run before holding. @@ -308,6 +311,7 @@ static void intel_uncore_forcewake_reset(struct drm_i915_private *dev_priv, assert_forcewakes_inactive(dev_priv); spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags); + iosf_mbi_punit_release(); } static u64 gen9_edram_size(struct drm_i915_private *dev_priv)