Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934354AbcKJPgW (ORCPT ); Thu, 10 Nov 2016 10:36:22 -0500 Received: from iolanthe.rowland.org ([192.131.102.54]:55400 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S934314AbcKJPgU (ORCPT ); Thu, 10 Nov 2016 10:36:20 -0500 Date: Thu, 10 Nov 2016 10:36:18 -0500 (EST) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Kai-Heng Feng cc: =?UTF-8?Q?Bj=C3=B8rn_Mork?= , 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=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 917 Lines: 29 On Thu, 10 Nov 2016, Kai-Heng Feng wrote: > Hi, > > On Wed, Nov 9, 2016 at 8:32 PM, Bjørn Mork wrote: > > Oliver Neukum writes: > > > >> On Tue, 2016-11-08 at 13:44 -0500, Alan Stern wrote: > >> > >>> These problems could very well be caused by running at SuperSpeed > >>> (USB-3) instead of high speed (USB-2). > > Yes, it's running at SuperSpeed, on a Kabylake laptop. > > It does not have this issue on a Broadwell laptop, also running at SuperSpeed. > > >>> > >>> Is there any way to test what happens when the device is attached to > >>> the computer by a USB-2 cable? That would prevent it from operating at > >>> SuperSpeed. > > I recall old Intel PCH can change the USB host from XHCI to EHCI, > newer PCH does not have this option. > > Is there a way to force XHCI run at HighSpeed? Yes, like I said above: Use a USB-2 cable instead of a USB-3 cable. Alan Stern