From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:43752 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754262AbdLDOBu (ORCPT ); Mon, 4 Dec 2017 09:01:50 -0500 Subject: Patch "drm/i915: Fix false-positive assert_rpm_wakelock_held in i915_pmic_bus_access_notifier v2" has been added to the 4.14-stable tree To: j.w.r.degoede@gmail.com, bugs-freedesktop@ubermail.me, gregkh@linuxfoundation.org, hdegoede@redhat.com, imre.deak@intel.com, jani.nikula@intel.com Cc: , From: Date: Mon, 04 Dec 2017 15:01:53 +0100 Message-ID: <1512396113229121@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled drm/i915: Fix false-positive assert_rpm_wakelock_held in i915_pmic_bus_access_notifier v2 to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-i915-fix-false-positive-assert_rpm_wakelock_held-in-i915_pmic_bus_access_notifier-v2.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From f4359cedfb43b934f38c50d1604db21333abe57b Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Fri, 10 Nov 2017 16:03:01 +0100 Subject: drm/i915: Fix false-positive assert_rpm_wakelock_held in i915_pmic_bus_access_notifier v2 From: Hans de Goede commit f4359cedfb43b934f38c50d1604db21333abe57b upstream. assert_rpm_wakelock_held is triggered from i915_pmic_bus_access_notifier even though it gets unregistered on (runtime) suspend, this is caused by a race happening under the following circumstances: intel_runtime_pm_put does: atomic_dec(&dev_priv->pm.wakeref_count); pm_runtime_mark_last_busy(kdev); pm_runtime_put_autosuspend(kdev); And pm_runtime_put_autosuspend calls intel_runtime_suspend from a workqueue, so there is ample of time between the atomic_dec() and intel_runtime_suspend() unregistering the notifier. If the notifier gets called in this windowd assert_rpm_wakelock_held falsely triggers (at this point we're not runtime-suspended yet). This commit adds disable_rpm_wakeref_asserts and enable_rpm_wakeref_asserts calls around the intel_uncore_forcewake_get(FORCEWAKE_ALL) call in i915_pmic_bus_access_notifier fixing the false-positive WARN_ON. Changes in v2: -Reword comment explaining why disabling the wakeref asserts is ok and necessary Reported-by: FKr Reviewed-by: Imre Deak Signed-off-by: Hans de Goede Link: https://patchwork.freedesktop.org/patch/msgid/20171110150301.9601-2-hdegoede@redhat.com (cherry picked from commit ce30560c80dead91e98a03d90fb8791e57a9b69d) Signed-off-by: Jani Nikula Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/i915/intel_uncore.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/drivers/gpu/drm/i915/intel_uncore.c +++ b/drivers/gpu/drm/i915/intel_uncore.c @@ -1171,8 +1171,15 @@ static int i915_pmic_bus_access_notifier * bus, which will be busy after this notification, leading to: * "render: timed out waiting for forcewake ack request." * errors. + * + * The notifier is unregistered during intel_runtime_suspend(), + * so it's ok to access the HW here without holding a RPM + * wake reference -> disable wakeref asserts for the time of + * the access. */ + disable_rpm_wakeref_asserts(dev_priv); intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL); + enable_rpm_wakeref_asserts(dev_priv); break; case MBI_PMIC_BUS_ACCESS_END: intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL); Patches currently in stable-queue which might be from j.w.r.degoede@gmail.com are queue-4.14/drm-i915-re-register-pmic-bus-access-notifier-on-runtime-resume.patch queue-4.14/drm-i915-fix-false-positive-assert_rpm_wakelock_held-in-i915_pmic_bus_access_notifier-v2.patch