From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oliver Neukum Subject: Re: [PATCH] usbnet: prevent device rpm suspend in usbnet_probe function Date: Wed, 09 Nov 2016 12:58:55 +0100 Message-ID: <1478692735.2428.10.camel@suse.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: bjorn@mork.no, Kai-Heng Feng , linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, netdev@vger.kernel.org To: Alan Stern Return-path: Received: from mx2.suse.de ([195.135.220.15]:43392 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751454AbcKIMEp (ORCPT ); Wed, 9 Nov 2016 07:04:45 -0500 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: 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). > > 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. > > The main point, however, is that the proposed patch doesn't seem to > address the true problem, which is that the device gets suspended > between probes. The patch only tries to prevent it from being > suspended during a probe -- which is already prevented by the USB core. But why doesn't it fail during normal operation? I suspect that its firmware requires the altsetting /* should we change control altsetting on a NCM/MBIM function? */ if (cdc_ncm_select_altsetting(intf) == CDC_NCM_COMM_ALTSETTING_MBIM) { data_altsetting = CDC_NCM_DATA_ALTSETTING_MBIM; ret = cdc_mbim_set_ctrlalt(dev, intf, CDC_NCM_COMM_ALTSETTING_MBIM); to be set before it accepts a suspension. Regards Oliver