Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753534AbcKHPZb (ORCPT ); Tue, 8 Nov 2016 10:25:31 -0500 Received: from iolanthe.rowland.org ([192.131.102.54]:33020 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751427AbcKHPZ2 (ORCPT ); Tue, 8 Nov 2016 10:25:28 -0500 Date: Tue, 8 Nov 2016 10:25:26 -0500 (EST) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Kai-Heng Feng cc: Oliver Neukum , , , Subject: Re: [PATCH] usbnet: prevent device rpm suspend in usbnet_probe function In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1525 Lines: 41 On Tue, 8 Nov 2016, Kai-Heng Feng wrote: > Hi, > > On Mon, Nov 7, 2016 at 7:02 PM, Oliver Neukum wrote: > > On Fri, 2016-11-04 at 17:57 +0800, Kai-Heng Feng wrote: > >> Sometimes cdc_mbim failed to probe if runtime pm is enabled: > >> [ 9.305626] cdc_mbim: probe of 2-2:1.12 failed with error -22 > >> > >> This can be solved by increase its pm usage counter. > >> > >> Signed-off-by: Kai-Heng Feng > > > > For the record: > > > > NAK. This fixes a symptom. If this patch helps something is broken in > > device core. We need to find that. > > > > Please check attached dmesg with usbcore.dyndbg="+p". The log shows that the device went into suspend _before_ the cdc_mbim driver was probed, not during the probe. Then just before the probe was started, the USB core tried to resume the device and the resume failed. The log shows a bunch of other problems with this device: [ 3.862253] usb 2-2: config 1 has an invalid interface number: 12 but max is 1 [ 3.862254] usb 2-2: config 1 has an invalid interface number: 13 but max is 1 [ 3.862254] usb 2-2: config 1 has an invalid interface number: 13 but max is 1 [ 3.862255] usb 2-2: config 1 has no interface number 0 [ 3.862256] usb 2-2: config 1 has no interface number 1 ... [ 8.295180] usb 2-2: Disable of device-initiated U1 failed. [ 8.295322] usb 2-2: Disable of device-initiated U2 failed. I get the impression that the device won't work properly with runtime PM at all. Alan Stern