From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 239ECECAAA1 for ; Tue, 6 Sep 2022 16:02:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238522AbiIFQC0 (ORCPT ); Tue, 6 Sep 2022 12:02:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36110 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233615AbiIFQCH (ORCPT ); Tue, 6 Sep 2022 12:02:07 -0400 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D6BE392F44; Tue, 6 Sep 2022 08:22:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1662477735; x=1694013735; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=pvrR9AaLZeSwwdJMT20ILWHfqE4EnXxLAynRB+jX/wQ=; b=Um8gNvqCvUVyx8LaKk16gyE6h8lS6nQ7vGfMfL0UD0FBVyU/oMurtOlr QAiMwMq7Mm6Da8SmBKQmU9Y74lkA9RrpTKboCyLYf/0las1kh59hM0u0N 18NozXJRxTQ3GiQtrPE+FtOFdV8GWP9oes4yuZVuaMpfvfWsEPLfIuZf7 MEEDBTtvuzk17MvnzjE0zVsbXYq1CMOv8ym4LBhP5Ts5Hf4MXIelCB1sk 1vYaqIVbIVodGKyn1NVtG/HHnd5fgHnWB6kENpI8QV23RipOr2VywMmwm qRKYVdQ6ejLrmDL+TXtolWBmtZlOCHF0jPM65miwngnBlQi7TsSk38pY6 g==; X-IronPort-AV: E=McAfee;i="6500,9779,10462"; a="297405550" X-IronPort-AV: E=Sophos;i="5.93,294,1654585200"; d="scan'208";a="297405550" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Sep 2022 08:22:13 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.93,294,1654585200"; d="scan'208";a="675734200" Received: from black.fi.intel.com ([10.237.72.28]) by fmsmga008.fm.intel.com with ESMTP; 06 Sep 2022 08:22:11 -0700 Received: by black.fi.intel.com (Postfix, from userid 1001) id 5BF0586; Tue, 6 Sep 2022 18:22:27 +0300 (EEST) Date: Tue, 6 Sep 2022 18:22:27 +0300 From: Mika Westerberg To: Kai-Heng Feng Cc: andreas.noever@gmail.com, michael.jamet@intel.com, YehezkelShB@gmail.com, sanju.mehta@amd.com, mario.limonciello@amd.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] thunderbolt: Resume PCIe bridges after switch is found on AMD USB4 controller Message-ID: References: <20220905065622.1573811-1-kai.heng.feng@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 06, 2022 at 05:59:49PM +0300, Mika Westerberg wrote: > This reminded me that in Intel hardware there is an ACPI power resource that is > shared between related devices. IIRC there is _PR0() method under the root > port, xHCI and the TBT NHI that returns the same power resource. Now, when the > power resource is turned on for any of the devices the kernel wakes up the rest > too to make sure they get properly re-initialized if they went into > D0unitialized or something like that. The commit that added this is > 4533771c1e53 ("ACPI / PM: Introduce concept of a _PR0 dependent device"). Probably has nothing to do with this actually.