From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from esa.hc5016-32.iphmx.com (esa.hc5016-32.iphmx.com [207.54.87.100]) (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 A933341A569; Mon, 27 Jul 2026 13:32:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=207.54.87.100 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785159166; cv=none; b=NV9jGqRrhmR7kxyGq5g3Lz+c7tHgJabJATa2l0Z72xH9agJ5We5g2xOgYeNA4fZCqTQkyYWWHyiV0JeihBMgSNWnbC5mwWXL9KGMVPBRwK1sFStjv9U7jQsbmg/PbZcC/uOEVaH9QDh6XB1L1X3VUoiglRPoTx9QW+rhi+OAhFA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785159166; c=relaxed/simple; bh=lvjFxcdcPlxe5y3oQfMMGbt+KFUWox48zQVzoOwO47Y=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ps+Wxnqmhuo8CRAydSpTlPrK0XagMO5NPPFy7L/VWkDvk3DI7xLdkAPHEOkSPNKPE3fpQjG2NUCtIvchAnYlZJ9wJgyr6yQEDc0SiDRiN27j6s3SOEjf7S90wp7ClOeASjoZzcHx9joqsaFfAiS7FytiY17D2L0JDzLxnqt7vWs= 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=ee7pGBlZ; arc=none smtp.client-ip=207.54.87.100 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="ee7pGBlZ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=harman.com; i=@harman.com; q=dns/txt; s=CES-HARMAN1; t=1785159164; x=1816695164; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=AX4cyBfkVmtItWN66pXo1qA418loJXkfALdGa3eCdFc=; b=ee7pGBlZiEQmXXPQkSaHG2ucdW2jIKtbVqpXwPWqBMKn1wxcUxHR4NWv As/3dHMWuv0QUW2yI2yIOdVAgve64FtqT4Kv4lnEUQdmm3HcIOPjhToYW dqCWRKhyx5qS/kfHAIInLP+UHqOTIVyLYjRYmDqSRGNWXQyu/o69iA50B 6GyUCKpbqoxUk7i2ppuTfPe5thrfk7FLff5V5r4KfFn8NeSXxTvszHA7v 2UrtpR8+8kq/pWIfASrIXuAP3OjiNYBM7cQ63/K0e6PTPzE2sp4V+/sDv NIbelgj5GdbZAX9p6DXj89oVz80Wq4FkloVpj4SCwbAFhBq1eAMN4yrMU Q==; X-CSE-ConnectionGUID: 5uIQVk6ZSlatejKiGQf4tg== X-CSE-MsgGUID: UkFPcrSoTRmr+v5dsLoiEQ== X-IronPort-AV: E=McAfee;i="6800,10657,11858"; a="119158545" X-IronPort-AV: E=Sophos;i="6.25,188,1779163200"; d="scan'208";a="119158545" 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 esa11.hc5016-32.iphmx.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jul 2026 09:32:35 -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, 27 Jul 2026 19:02:33 +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, 27 Jul 2026 19:02:33 +0530 Received: by awsmblx423bs002.localdomain (Postfix, from userid 530975) id 421A68AEE1; Mon, 27 Jul 2026 13:32:32 +0000 (UTC) From: Akshay Gujar To: CC: , , , , , Subject: Re: [PATCH v5 2/3] Documentation: ABI: document DEVICE_ENUMERATION_FAILURE uevent Date: Mon, 27 Jul 2026 13:32:32 +0000 Message-ID: <20260727133232.556324-1-Akshay.Gujar@harman.com> X-Mailer: git-send-email 2.19.0 In-Reply-To: <2026072515-pueblo-appealing-e245@gregkh> References: <2026072515-pueblo-appealing-e245@gregkh> 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 On Sat, Jul 25, 2026 at 07:21:30AM +0200, Greg KH wrote: > > > > +What: DEVICE_ENUMERATION_FAILURE > > > > +Date: July 2026 > > > > +KernelVersion: 7.3 > > > > +Description: > > > > + Some devices may be detected but fail to enumerate > > > > + due to protocol-level errors or invalid responses. > > > > + > > > > + A KOBJ_CHANGE uevent includes the following environment > > > > + variable when this occurs: > > > > + > > > > + DEVICE_ENUMERATION_FAILURE= > > > > + > > > > + The value is the kernel device name of the device for > > > > + which enumeration failed, as returned by dev_name(). > > > > + > > > > + Example (USB): > > > > + > > > > + ACTION=change > > > > + SUBSYSTEM=usb > > > > + DEVTYPE=usb_interface > > > > > > This will be the port device, not the usb interface, right? > > > > No, DEVTYPE=usb_interface is correct, the example was captured on > > real hardware. The uevent is not emitted from the port device itself. > > usb_port devices have no bus or class, so dev_uevent_filter() > > drops any event from them.It is emitted from the port's parent, > > the hub's usb_interface device, while the failing port is identified in the payload instead. > So shouldn't we fix the fact that usb_ports are not on the bus and add > them to one? Would that make things more obvious here as to what port > the issue is happening on, and potentially allow userspace to actually > figure out which physical port the problem is? Adding usb_port devices to usb_bus_type does not fit. usb_device_match() only handles usb_device and usb_interface, so ports would fall through unmatched, and bus-managed binding would conflict with the existing usb_port_driver assignment. Userspace can already resolve the physical port directly from the event today: DEVPATH=/devices/.../usb1/1-0:1.0 DEVICE_ENUMERATION_FAILURE=usb1-port1 which corresponds to: -> /sys/devices/.../usb1/1-0:1.0/usb1-port1 Appending the payload name to DEVPATH gives the exact sysfs path to the failing port on the hub. I dropped the DEVPATH line from the documentation example by mistake. Will restore it in v6 so the emitter/payload relationship is clear. Thanks, Akshay