Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755159AbbDGW6n (ORCPT ); Tue, 7 Apr 2015 18:58:43 -0400 Received: from exprod5og109.obsmtp.com ([64.18.0.188]:58072 "EHLO mail-ob0-f169.google.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755134AbbDGW6h (ORCPT ); Tue, 7 Apr 2015 18:58:37 -0400 MIME-Version: 1.0 In-Reply-To: <11619620.g1RKbURH6u@vostro.rjw.lan> References: <1427836680-13008-1-git-send-email-fkan@apm.com> <20150407084143.GP17830@lahna.fi.intel.com> <11619620.g1RKbURH6u@vostro.rjw.lan> Date: Tue, 7 Apr 2015 15:58:36 -0700 Message-ID: Subject: Re: [PATCH] mailbox: add ACPI support for mailbox framework From: Feng Kan To: "Rafael J. Wysocki" Cc: Mika Westerberg , patches , Jassi Brar , "linux-kernel@vger.kernel.org" , "linux-acpi@vger.kernel.org" Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3859 Lines: 86 On Tue, Apr 7, 2015 at 4:37 AM, Rafael J. Wysocki wrote: > On Tuesday, April 07, 2015 11:41:43 AM Mika Westerberg wrote: >> On Thu, Apr 02, 2015 at 11:04:24AM -0700, Feng Kan wrote: >> > On Thu, Apr 2, 2015 at 2:07 AM, Mika Westerberg >> > wrote: >> > > On Wed, Apr 01, 2015 at 10:01:45AM -0700, Feng Kan wrote: >> > >> On Wed, Apr 1, 2015 at 12:45 AM, Mika Westerberg >> > >> wrote: >> > >> > On Tue, Mar 31, 2015 at 02:18:00PM -0700, Feng Kan wrote: >> > >> >> This will add support for ACPI parsing of the mboxes attribute >> > >> >> when booting with ACPI table. The client will have a attribute >> > >> >> mimic the dts call "mboxes". In the ACPI case, the client will >> > >> >> mark "mboxes" with the ACPI HID of the mbox it wishes to use. >> > >> >> >> > >> >> Name (_DSD, Package () { >> > >> >> ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), >> > >> >> Package () { >> > >> >> Package (2) {"mboxes", "ACPIHID"}, >> > >> >> } >> > >> >> }) >> > >> > >> > >> > Instead of this, why not match against the DT compatible property? >> > >> > >> > >> > Name (_HID, "PRP0001") >> > >> > >> > >> > Name (_DSD, Package () { >> > >> > ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), >> > >> > Package () { >> > >> > Package (2) {"compatible", "your-dt-compatible-string"}, >> > >> > } >> > >> > }) >> > >> I think my description was not clear enough. The _DSD section is not >> > >> meant to identify the mailbox driver, but used by the acpi node that will >> > >> request the mailbox channel. The dts version would be as below. >> > >> >> > >> mailbox: { >> > >> } >> > >> >> > >> user-mbox: { >> > >> mboxes: <&mailbox 0> >> > >> } >> > >> >> > >> The mboxes attribute in the user of the mbox has to specify the HID of the >> > >> mbox in order to retrieve channel pointer. >> > > >> > > Okay, then I think you can use reference instead of _HID, like >> > > >> > > // The mailbox device >> > > Device (MLBX) { >> > > } >> > > >> > > // User-mbox device >> > > Device (USBX) { >> > > Name (_DSD, Package () { >> > > ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), >> > > Package () { >> > > Package () {"mboxes", Package () {^^MLBX, 0}}), >> > > } >> > > }) >> > > } >> > >> > Thanks, will try this. A side question on your previous reply. Would you >> > prefer a new driver using the PRP0001 or an actual proper HID. >> >> If you have existing DT bindings for this, then PRP0001 is fine. >> Otherwise you should use the proper _HID for this particular device. > > To be precise, PRP0001 specifically means "Use the 'compatible' property > to find the driver for this device", so if *that* is what you want to do, I am a bit uneasy about this. I understand the application of this. For a system that is both DT and ACPI compatible, this would open up a flood of PRP0001 device drivers. What is the guideline here? Is this PRP0001 only exist to support legacy devices that do not have a proper HID. > you can use PRP0001 as the _HID. For Windows (and such) compatibility, you > can provide a _CID whith a (list of) proper device ID(s) in addition to that. > > > -- > I speak only for myself. > Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/