Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754694AbcDZXx6 (ORCPT ); Tue, 26 Apr 2016 19:53:58 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:40432 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753162AbcDZXOO (ORCPT ); Tue, 26 Apr 2016 19:14:14 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Oliver Neukum" , "Greg Kroah-Hartman" Date: Wed, 27 Apr 2016 01:02:21 +0200 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 023/217] usb: retry reset if a device times out In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8426:ae4:c500:9cba:69ae:962d:6167 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1424 Lines: 42 3.16.35-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Oliver Neukum commit 264904ccc33c604d4b3141bbd33808152dfac45b upstream. Some devices I got show an inability to operate right after power on if they are already connected. They are beyond recovery if the descriptors are requested multiple times. So in case of a timeout we rather bail early and reset again. But it must be done only on the first loop lest we get into a reset/time out spiral that can be overcome with a retry. This patch is a rework of a patch that fell through the cracks. http://www.spinics.net/lists/linux-usb/msg103263.html Signed-off-by: Oliver Neukum Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings --- drivers/usb/core/hub.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -4370,7 +4370,13 @@ hub_port_init (struct usb_hub *hub, stru r = -EPROTO; break; } - if (r == 0) + /* + * Some devices time out if they are powered on + * when already connected. They need a second + * reset. But only on the first attempt, + * lest we get into a time out/reset loop + */ + if (r == 0 || (r == -ETIMEDOUT && j == 0)) break; } udev->descriptor.bMaxPacketSize0 =