From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.15]) (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 EF7FD2797A0; Thu, 10 Jul 2025 17:03:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.15 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752166998; cv=none; b=k3ePJHeIxiVcuWTaWXz+05nbT/xDjt40ZBqFuaGBfzK7jGDi4h9hxhpL/KX/4cnr117bfvAsgY3WvqDKTUfqPebgrLvtc9vjqPHpqZzxDZ8r0VyTe4UXs8tiV/rV7MFCQ3ZuGb7qtPS+o9xNoLdga2XN3ZNKfCBWAA7KsiyFzkM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752166998; c=relaxed/simple; bh=W7zbUH+rxVwiXWiCIcevxN/uLfmclgsMQLofiJFemE8=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=DpE11Fzch2RRJ+vgGOG5j7P6S6iyDiwPBchPr4NlwAjjvScgP93hQ6CKn0V11Sm5BblcOqVbAcliEwia7lYeQTJHsvHxGEwvB10wNMvL67uo4YtYVdeimH2zZ15tpi5ABVyYELs0QmJYk+toti++kF+gkS9AWwalEAN3Gg9FHr8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=g2UKz81w; arc=none smtp.client-ip=192.198.163.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="g2UKz81w" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1752166997; x=1783702997; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=W7zbUH+rxVwiXWiCIcevxN/uLfmclgsMQLofiJFemE8=; b=g2UKz81w9OmiifzRG7UjxBwNPU2lRFSL4JOnnSPaOc7/ga863nI/zehy 3wyO+F/IGfQvQjsJ1v/vu0FCpL7oWt5aGVjRrWxNboyJX6VLoXbDlXqQz ZdIaWIVHzAqLpxl+3FgVkuF8xSDKhI9uXuCrl6zSUv+DcIRb+8zwrfZX6 t40MG4QYkUfje8tNDzF1yjqn2sDa85ezg+pQxJ613FfRBHduGHf0Pz2Cb N8i0iMoTfq+IVj9WT4DJNpZG6xnBvzwMXBuOtedTkf3dEvWEW14RPCJoA 9K/CIz8srGkNElYckqId1DpvrCsBNB/aDOpPqmTCKw8UDVkbRhcTwFPyz Q==; X-CSE-ConnectionGUID: 7j6GJ7G4TxC8T0HKNDv6Fw== X-CSE-MsgGUID: FcXhll5BQZ2PDrz2+Tb2fQ== X-IronPort-AV: E=McAfee;i="6800,10657,11490"; a="54611069" X-IronPort-AV: E=Sophos;i="6.16,301,1744095600"; d="scan'208";a="54611069" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by fmvoesa109.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Jul 2025 10:02:32 -0700 X-CSE-ConnectionGUID: e3p89pHySIe68v8tQzAc5g== X-CSE-MsgGUID: Jwe4w9AYQymXoADwzaUQow== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,301,1744095600"; d="scan'208";a="161710434" Received: from black.fi.intel.com ([10.237.72.28]) by fmviesa004.fm.intel.com with ESMTP; 10 Jul 2025 10:02:30 -0700 Received: by black.fi.intel.com (Postfix, from userid 1003) id C43FB1A1; Thu, 10 Jul 2025 20:02:28 +0300 (EEST) From: Andy Shevchenko To: Andy Shevchenko , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org Cc: "Rafael J. Wysocki" , Len Brown , Yevhen Kondrashyn , stable@vger.kernel.org Subject: [PATCH v1 1/1] Documentation: ACPI: Fix parent device references Date: Thu, 10 Jul 2025 20:00:23 +0300 Message-ID: <20250710170225.961303-1-andriy.shevchenko@linux.intel.com> X-Mailer: git-send-email 2.47.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The _CRS resources in many cases want to have ResourceSource field to be a type of ACPI String. This means that to compile properly we need to enclosure the name path into double quotes. This will in practice defer the interpretation to a run-time stage, However, this may be interpreted differently on different OSes and ACPI interpreter implementations. In particular ACPICA might not correctly recognize the leading '^' (caret) character and will not resolve the relative name path properly. On top of that, this piece may be used in SSDTs which are loaded after the DSDT and on itself may also not resolve relative name paths outside of their own scopes. With this all said, fix documentation to use fully-qualified name paths always to avoid any misinterpretations, which is proven to work. Fixes: 8eb5c87a92c0 ("i2c: add ACPI support for I2C mux ports") Reported-by: Yevhen Kondrashyn Cc: stable@vger.kernel.org Signed-off-by: Andy Shevchenko --- Rafael, I prefer, if no objections, to push this as v6.16-rc6 material since the reported issue was detected on old (v5.10.y) and still LTS kernel. Would be nice for people to not trap to it in older kernels. Documentation/firmware-guide/acpi/i2c-muxes.rst | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/Documentation/firmware-guide/acpi/i2c-muxes.rst b/Documentation/firmware-guide/acpi/i2c-muxes.rst index 3a8997ccd7c4..f366539acd79 100644 --- a/Documentation/firmware-guide/acpi/i2c-muxes.rst +++ b/Documentation/firmware-guide/acpi/i2c-muxes.rst @@ -14,7 +14,7 @@ Consider this topology:: | | | 0x70 |--CH01--> i2c client B (0x50) +------+ +------+ -which corresponds to the following ASL:: +which corresponds to the following ASL (in the scope of \_SB):: Device (SMB1) { @@ -24,7 +24,7 @@ which corresponds to the following ASL:: Name (_HID, ...) Name (_CRS, ResourceTemplate () { I2cSerialBus (0x70, ControllerInitiated, I2C_SPEED, - AddressingMode7Bit, "^SMB1", 0x00, + AddressingMode7Bit, "\\_SB.SMB1", 0x00, ResourceConsumer,,) } @@ -37,7 +37,7 @@ which corresponds to the following ASL:: Name (_HID, ...) Name (_CRS, ResourceTemplate () { I2cSerialBus (0x50, ControllerInitiated, I2C_SPEED, - AddressingMode7Bit, "^CH00", 0x00, + AddressingMode7Bit, "\\_SB.SMB1.CH00", 0x00, ResourceConsumer,,) } } @@ -52,7 +52,7 @@ which corresponds to the following ASL:: Name (_HID, ...) Name (_CRS, ResourceTemplate () { I2cSerialBus (0x50, ControllerInitiated, I2C_SPEED, - AddressingMode7Bit, "^CH01", 0x00, + AddressingMode7Bit, "\\_SB.SMB1.CH01", 0x00, ResourceConsumer,,) } } -- 2.47.2