From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752340AbdGOBjF (ORCPT ); Fri, 14 Jul 2017 21:39:05 -0400 Received: from omzsmtpe01.verizonbusiness.com ([199.249.25.210]:53795 "EHLO omzsmtpe01.verizonbusiness.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751419AbdGOB1S (ORCPT ); Fri, 14 Jul 2017 21:27:18 -0400 X-IronPort-Anti-Spam-Filtered: false From: "Levin, Alexander (Sasha Levin)" Cc: "Rafael J. Wysocki" , "Levin, Alexander (Sasha Levin)" X-Host: discovery.odc.vzwcorp.com To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [PATCH for v4.9 LTS 32/87] ACPI / scan: Prefer devices without _HID/_CID for _ADR matching Thread-Topic: [PATCH for v4.9 LTS 32/87] ACPI / scan: Prefer devices without _HID/_CID for _ADR matching Thread-Index: AQHS/QlVvHcQXhoKzE2s2x66YWnAfA== Date: Sat, 15 Jul 2017 01:26:07 +0000 Message-ID: <20170715012538.10101-32-alexander.levin@verizon.com> References: <20170715012538.10101-1-alexander.levin@verizon.com> In-Reply-To: <20170715012538.10101-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="iso-8859-1" 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 quoted-printable to 8bit by nfs id v6F1dcjg023248 From: "Rafael J. Wysocki" [ Upstream commit c2a6bbaf0c5f90463a7011a295bbdb7e33c80b51 ] The way acpi_find_child_device() works currently is that, if there are two (or more) devices with the same _ADR value in the same namespace scope (which is not specifically allowed by the spec and the OS behavior in that case is not defined), the first one of them found to be present (with the help of _STA) will be returned. This covers the majority of cases, but is not sufficient if some of the devices in question have a _HID (or _CID) returning some valid ACPI/PNP device IDs (which is disallowed by the spec) and the ASL writers' expectation appears to be that the OS will match devices without a valid ACPI/PNP device ID against a given bus address first. To cover this special case as well, modify find_child_checks() to prefer devices without ACPI/PNP device IDs over devices that have them. Suggested-by: Mika Westerberg Signed-off-by: Rafael J. Wysocki Tested-by: Hans de Goede Signed-off-by: Sasha Levin --- drivers/acpi/glue.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c index 5ea5dc219f56..73c9c7fa9001 100644 --- a/drivers/acpi/glue.c +++ b/drivers/acpi/glue.c @@ -98,7 +98,15 @@ static int find_child_checks(struct acpi_device *adev, bool check_children) if (check_children && list_empty(&adev->children)) return -ENODEV; - return sta_present ? FIND_CHILD_MAX_SCORE : FIND_CHILD_MIN_SCORE; + /* + * If the device has a _HID (or _CID) returning a valid ACPI/PNP + * device ID, it is better to make it look less attractive here, so that + * the other device with the same _ADR value (that may not have a valid + * device ID) can be matched going forward. [This means a second spec + * violation in a row, so whatever we do here is best effort anyway.] + */ + return sta_present && list_empty(&adev->pnp.ids) ? + FIND_CHILD_MAX_SCORE : FIND_CHILD_MIN_SCORE; } struct acpi_device *acpi_find_child_device(struct acpi_device *parent, -- 2.11.0