From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:42602 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751843AbcGMXEp (ORCPT ); Wed, 13 Jul 2016 19:04:45 -0400 Subject: Patch "cdc_ncm: workaround for EM7455 "silent" data interface" has been added to the 3.14-stable tree To: bjorn@mork.no, aleksander@aleksander.es, andreas.fett@secunet.com, davem@davemloft.net, gregkh@linuxfoundation.org, ml001@armbruster-it.de, ralph@purejava.org, rasmus@lerdorf.com, samo.ratnik@gmail.com Cc: , From: Date: Thu, 14 Jul 2016 08:04:54 +0900 Message-ID: <146845109490150@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled cdc_ncm: workaround for EM7455 "silent" data interface to the 3.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: cdc_ncm-workaround-for-em7455-silent-data-interface.patch and it can be found in the queue-3.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Thu Jul 14 07:36:31 JST 2016 From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= Date: Sun, 3 Jul 2016 22:24:50 +0200 Subject: cdc_ncm: workaround for EM7455 "silent" data interface MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= [ Upstream commit c086e7096170390594c425114d98172bc9aceb8a ] Several Lenovo users have reported problems with their Sierra Wireless EM7455 modem. The driver has loaded successfully and the MBIM management channel has appeared to work, including establishing a connection to the mobile network. But no frames have been received over the data interface. The problem affects all EM7455 and MC7455, and is assumed to affect other modems based on the same Qualcomm chipset and baseband firmware. Testing narrowed the problem down to what seems to be a firmware timing bug during initialization. Adding a short sleep while probing is sufficient to make the problem disappear. Experiments have shown that 1-2 ms is too little to have any effect, while 10-20 ms is enough to reliably succeed. Reported-by: Stefan Armbruster Reported-by: Ralph Plawetzki Reported-by: Andreas Fett Reported-by: Rasmus Lerdorf Reported-by: Samo Ratnik Reported-and-tested-by: Aleksander Morgado Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/usb/cdc_ncm.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -438,6 +438,13 @@ advance: if (cdc_ncm_setup(dev)) goto error2; + /* Some firmwares need a pause here or they will silently fail + * to set up the interface properly. This value was decided + * empirically on a Sierra Wireless MC7455 running 02.08.02.00 + * firmware. + */ + usleep_range(10000, 20000); + /* configure data interface */ temp = usb_set_interface(dev->udev, iface_no, data_altsetting); if (temp) { Patches currently in stable-queue which might be from bjorn@mork.no are queue-3.14/cdc_ncm-workaround-for-em7455-silent-data-interface.patch