Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752679AbcKGKiO (ORCPT ); Mon, 7 Nov 2016 05:38:14 -0500 Received: from mx2.suse.de ([195.135.220.15]:46734 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752015AbcKGKiN (ORCPT ); Mon, 7 Nov 2016 05:38:13 -0500 Message-ID: <1478514745.2400.3.camel@suse.com> Subject: Re: [PATCH] usbnet: prevent device rpm suspend in usbnet_probe function From: Oliver Neukum To: Alan Stern Cc: Kai-Heng Feng , linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, netdev@vger.kernel.org Date: Mon, 07 Nov 2016 11:32:25 +0100 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.12.11 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 634 Lines: 22 On Fri, 2016-11-04 at 09:26 -0400, Alan Stern wrote: > On Fri, 4 Nov 2016, 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. > > This should not be needed. The USB core increments the PM usage > counter of a device before probing its interfaces. Indeed. Yet we have experimental evidence. Kai-Heng Feng, could you please enable dynamic debugging for drivers/usb/core/driver.c so that we can see what is going on with the usage counters? Regards Oliver