From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752625AbdIFTud (ORCPT ); Wed, 6 Sep 2017 15:50:33 -0400 Received: from esa5.dell-outbound.iphmx.com ([68.232.153.95]:55208 "EHLO esa5.dell-outbound.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751969AbdIFTua (ORCPT ); Wed, 6 Sep 2017 15:50:30 -0400 From: X-LoopCount0: from 10.175.216.250 X-IronPort-AV: E=Sophos;i="5.42,355,1500958800"; d="scan'208";a="546929848" X-DLP: DLP_GlobalPCIDSS To: CC: , , , , Subject: RE: Fwd: [PATCH] Add driver to force WMI Thunderbolt controller power status Thread-Topic: Fwd: [PATCH] Add driver to force WMI Thunderbolt controller power status Thread-Index: AQHTJ0YV8o1w6haZs0+qP3ceDgEFGaKoQZmAgAABehA= Date: Wed, 6 Sep 2017 19:49:32 +0000 Message-ID: References: <1504720440-24423-1-git-send-email-mario.limonciello@dell.com> <1504726863.2677.154.camel@intel.com> In-Reply-To: <1504726863.2677.154.camel@intel.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.143.242.75] Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by nfs id v86Jodwn027215 > -----Original Message----- > From: Bernat, Yehezkel [mailto:yehezkel.bernat@intel.com] > Sent: Wednesday, September 6, 2017 2:41 PM > To: Limonciello, Mario > Cc: mika.westerberg@linux.intel.com; linux-kernel@vger.kernel.org; platform- > driver-x86@vger.ke; dvhart@infradead.org; hughsient@gmail.com > Subject: Re: Fwd: [PATCH] Add driver to force WMI Thunderbolt controller power > status > > > > Current implementations of Intel Thunderbolt controllers will go > > into a low power mode when not in use. > > > > Many machines containing these controllers also have a GPIO wired up > > that can force the controller awake.  This is offered via a ACPI-WMI > > interface intended to be manipulated by a userspace utility. > > > > This mechanism is provided by Intel to OEMs to include in BIOS. > > It uses an industry wide GUID that is populated in a separate _WDG > > entry with no binary MOF. > > > > This interface allow software such as fwupd to wake up thunderbolt > > controllers to query the firmware version or flash new firmware. > > As this is a Thunderbolt specific function, maybe it's better to be > exposed from the Thunderbolt driver? > I thought about this too, but the thunderbolt driver won't load if the controller doesn't exist in the first place, whereas this is a platform BIOS feature. I'll be interested to hear if Mika has a different perspective on if this should live in the TBT driver and the proper way to do it. > > > + > > +static DEVICE_ATTR_WO(force_power); > > + > > I'm not sure what is the convention for permissions for this type of > attributes but I feel like this worth being root-only writable, as it > can be used to power-off the controller in the middle of a FW update, > for example. Yeah I think you're right. I'll adjust it in a follow up patch if this is the correct way to go afterall. Thanks,