From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from esa.hc5016-32.iphmx.com (esa.hc5016-32.iphmx.com [207.54.81.235]) (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 4AFFD33122A; Sun, 2 Aug 2026 23:32:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=207.54.81.235 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785713545; cv=none; b=Rek8e3BYOciE3tEptocspmUClq5mgyznUlMblQRsJLTRwNZh8QM5hzm4RKIHjbzvuGC4VyOSUgD1GNuMIAJe7ONbOQwwRQs41/THBl9Y71DxLBMkZoeFIKtkcR4EuUXQ65EaEF1JUI5pWmet7Pg3SE/X/jp4EuSCjQDgW6qnTCY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785713545; c=relaxed/simple; bh=bbxuJ6Ua5w0m6Lru2hj8S1WU1keC+8be1ZyXN4cLPoE=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=jiLNStlSrBlWE5cf7JUaYVbNCAaYfmrwf9vJuJ7tGbj3S3dMnBLD9fjUaYhJmJUeuYDXlMiNkOnNEZeBaISqdL+5g5NkdhGSL2cJPp6/Zn9wj3jM9VG8pcc73lKqH6QmwJbT6xjxMucSg+zBdZIeKSh9re5WNon4qepKCajZ+kk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=harman.com; spf=pass smtp.mailfrom=harman.com; dkim=pass (2048-bit key) header.d=harman.com header.i=@harman.com header.b=GNqq1OTF; arc=none smtp.client-ip=207.54.81.235 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=harman.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=harman.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=harman.com header.i=@harman.com header.b="GNqq1OTF" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=harman.com; i=@harman.com; q=dns/txt; s=CES-HARMAN1; t=1785713544; x=1817249544; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=VKGYXRaxFBGBBiNMuo+qEYq8pPvopM49W6MPT33y15c=; b=GNqq1OTFnsvTB8zeDb+Du7BQ0ZAySY7Sm3Ud84yqGs3xvcug08Uoh9yE qJ0mHEVwSuuCpgpxgV/YQzHyqtPoz6QBdrmKzjp2PMRbqk+F5M+5KvlDj sqCw4T8I3G25mu0RRa5wsEMnloFzQLUqe7kGQLTsuXzg9B/ocAjGZx5JB 7pafq5T4TtrDImess5xdKDhH1hRmRg8II9vh129wnbUTdIAzmWLGe1crV 7ndzDUXXM66WgxL/51rlJkSBFMZcSGaj06BeWCIJAwva++44h13eNz5C9 SBK1k89CQEzrZZycPdbCDfoxeaOsLt20Dg2ni32XfkBSokcEuPVky2t7z Q==; X-CSE-ConnectionGUID: 3uHEfVXNQYGZdHK0W2M7Fg== X-CSE-MsgGUID: ohypSOJAQm+FDY7bUOihXQ== X-IronPort-AV: E=McAfee;i="6800,10657,11863"; a="117645078" X-IronPort-AV: E=Sophos;i="6.25,201,1779163200"; d="scan'208";a="117645078" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from unknown (HELO INMDWSHYB09.ad.harman.com) ([199.27.113.4]) by esa5.hc5016-32.iphmx.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Aug 2026 19:31:15 -0400 Received: from INMDWSHYB09.ad.harman.com (10.92.6.246) by INMDWSHYB09.ad.harman.com (10.92.6.246) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.43; Mon, 3 Aug 2026 05:01:12 +0530 Received: from awsmblx423bs002.localdomain (10.63.34.68) by INMDWSHYB09.ad.harman.com (10.92.6.254) with Microsoft SMTP Server id 15.2.2562.43 via Frontend Transport; Mon, 3 Aug 2026 05:01:12 +0530 Received: by awsmblx423bs002.localdomain (Postfix, from userid 530975) id E5AEA80059; Sun, 2 Aug 2026 23:31:11 +0000 (UTC) From: Akshay Gujar To: CC: , , , , , Subject: [PATCH v6 2/3] Documentation: ABI: document DEVICE_ENUMERATION_FAILURE uevent Date: Sun, 2 Aug 2026 23:31:07 +0000 Message-ID: <20260802233108.70950-3-Akshay.Gujar@harman.com> X-Mailer: git-send-email 2.19.0 In-Reply-To: <20260802233108.70950-1-Akshay.Gujar@harman.com> References: <20260802233108.70950-1-Akshay.Gujar@harman.com> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain Document the DEVICE_ENUMERATION_FAILURE environment variable emitted in KOBJ_CHANGE uevents when device enumeration fails. Signed-off-by: Akshay Gujar --- Documentation/ABI/testing/sysfs-uevent | 37 ++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-uevent b/Documentation/ABI/testing/sysfs-uevent index 0b6227706b35e..6ace99f99daa3 100644 --- a/Documentation/ABI/testing/sysfs-uevent +++ b/Documentation/ABI/testing/sysfs-uevent @@ -49,3 +49,40 @@ Description: Users: udev, userspace tools generating synthetic uevents + +What: DEVICE_ENUMERATION_FAILURE +Date: August 2026 +KernelVersion: 7.3 +Description: + Some devices are detected as physically present but fail + to enumerate, for example due to protocol-level errors or + invalid responses. + + When this happens, a bus driver may emit a KOBJ_CHANGE + uevent containing: + + DEVICE_ENUMERATION_FAILURE= + + The value is a bus-specific identifier of the port or slot + on which enumeration failed, not the name of the device + that emitted the event. For USB this is the port device + name, e.g. "usb1-port1". + + Example (USB): + + ACTION=change + SUBSYSTEM=usb + DEVTYPE=usb_interface + DEVPATH=/devices/.../usb1/1-0:1.0 + DEVICE_ENUMERATION_FAILURE=usb1-port1 + + The event is emitted from the hub interface that owns the + port, so DEVPATH refers to the interface. Appending the + identifier to DEVPATH gives the failing port: + + /sys/devices/.../usb1/1-0:1.0/usb1-port1/ + +Users: + udev, userspace tools monitoring device enumeration + failures + -- 2.19.0