From nobody Fri Oct 2 07:46:58 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9D39D39D6F6; Mon, 3 Aug 2026 18:11:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785780676; cv=none; b=flyJnRFZhR/EGTWEP5TmIotaTGL+i7r4gcwZIPHSUwfcRGoJtbnJWmQqb5jww090O3G4cHgw6Avu0uKkSjqULw471KmVT0AOKRaIIebNfGZ9n2+0Fk5gxmeK200v3f4QOJtKGKxZSUfYLNqqAgnzMdlKBkkGHIbQ6FLgPiK+hLo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785780676; c=relaxed/simple; bh=VlB8ik3K/w+Mz9YdhToh8/rEVvPcaGHd7IqacymkKt8=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=pzzfKzk5OoWuCqq6hasyH8T0vOkefTJdsuWUHVP8H9FnCC8+ZT9/oCmuOSVAeaG6mKZ9RKtXzSoMvEHQp9vzqNC8vk4002WXfdBb6hJLb6dF8YZQy+lYVlGX1edyctZXwTHwnhsFjiUHqINc9ZUI8oFG8hX+n/sbPsxIt1gCskc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Xu04ZLaD; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Xu04ZLaD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1251C1F00A3F; Mon, 3 Aug 2026 18:11:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785780674; bh=ADmuhGyPnsQrVI3q0l1mWHXbtYHb6HXx7eCGIqiSASU=; h=From:To:Cc:Subject:Date; b=Xu04ZLaD9z00p21u8EFlaDnNxHYGOQ7X2gwqpY/wxUy8hHvuPB+OH0AUxI7YTvq4L GVkIYu8E4u4j6ySoNlPnmNtQC8Bkv9ZmxszJ3G7kRq6NEF6xeuLsRKaBMU5vnXwVSy uHCRUMqAZLeKaIxGQDSI4yTNceFxk0XXnRSJhAvij6qWyonWQfYbgXtAA5nItnEz65 HlS723qRwygvDhWETsQ/iu/E7G2+CK7AA+dDhxlirT9zC+B7rfhgZRHVjYucL85JvP hQTqs7+LyH4SnLuTlPLsDPxW4LTmHS1RXykOohJ6ufXuQY2brqiHbM/q7wjKomjPJt o/1PRgnBP7FuQ== From: "Rafael J. Wysocki" To: Linux PM Cc: Greg Kroah-Hartman , Alan Stern , LKML , Julian Silver Subject: [PATCH v1] intel_idle: Avoid using deep idle states during initialization Date: Mon, 03 Aug 2026 20:11:10 +0200 Message-ID: <5120454.31r3eYUQgx@rafael.j.wysocki> Organization: Linux Kernel Development - Intel Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Rafael J. Wysocki Commit c0f691388992 ("intel_idle: Use subsys_initcall_sync() for initialization") effectively made intel_idle initialize earlier which turns out to interfere with USB EHCI probing on some platforms [1]. Investigation led to the conclusion that this was related to allowing package idle states to be used earlier than before. Work around that issue by making intel_idle set a CPU latency QoS request to prevent package idle states from being used on all platforms supported by it for the duration of the device_initcall() initialization phase. Fixes: c0f691388992 ("intel_idle: Use subsys_initcall_sync() for initializa= tion") Reported-by: Julian Silver Closes: https://lore.kernel.org/linux-acpi/3353bdf3-4f33-44b1-809b-b0378bee= 5816@gmail.com/ Signed-off-by: Rafael J. Wysocki --- drivers/idle/intel_idle.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -53,6 +53,7 @@ #include #include #include +#include #include #include #include @@ -2822,6 +2823,9 @@ error: pr_info("Failed to adjust C-states with data from 'intel_idle.table'\n"); } =20 +#define INTEL_IDLE_INIT_QOS 20 +static struct pm_qos_request qos_req __initdata; + static int __init intel_idle_init(void) { const struct x86_cpu_id *id; @@ -2891,6 +2895,13 @@ static int __init intel_idle_init(void) if (retval) pr_warn("failed to initialized sysfs"); =20 + /* + * Some platforms, in particular the Intel S1200BTL motherboard, have a + * problem with using package idle states too early, so prevent that + * from taking place until the device_initcall() phase is over. + */ + cpu_latency_qos_add_request(&qos_req, INTEL_IDLE_INIT_QOS); + retval =3D cpuidle_register_driver(&intel_idle_driver); if (retval) { struct cpuidle_driver *drv =3D cpuidle_get_driver(); @@ -2915,6 +2926,9 @@ hp_setup_fail: intel_idle_cpuidle_devices_uninit(); cpuidle_unregister_driver(&intel_idle_driver); init_driver_fail: + if (cpu_latency_qos_request_active((&qos_req))) + cpu_latency_qos_remove_request(&qos_req); + intel_idle_sysfs_uninit(); free_percpu(intel_idle_cpuidle_devices); return retval; @@ -2922,6 +2934,15 @@ init_driver_fail: } subsys_initcall_sync(intel_idle_init); =20 +static int __init intel_idle_init_complete(void) +{ + if (cpu_latency_qos_request_active((&qos_req))) + cpu_latency_qos_remove_request(&qos_req); + + return 0; +} +device_initcall_sync(intel_idle_init_complete); + /* * We are not really modular, but we used to support that. Meaning we also * support "intel_idle.max_cstate=3D..." at boot and also a read-only expo= rt of