From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756202AbaIIJP3 (ORCPT ); Tue, 9 Sep 2014 05:15:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:2668 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754745AbaIIJP1 (ORCPT ); Tue, 9 Sep 2014 05:15:27 -0400 Message-ID: <540EC52C.3000804@redhat.com> Date: Tue, 09 Sep 2014 11:15:24 +0200 From: Hans de Goede User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: linux-usb , SCSI development list , Linux Kernel Mailing List Subject: [REGRESSION 3.17] scsi (uas) disks no longer using tagged command queuing 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 Hi All, While working on making error handling in the uas driver more robust, I noticed that all the commands being send to a sata ssd hooked up over uas were untagged, where I would expect tcq to be used, as that is the big advantage of uas over usb-storage / bot. Taking the uas.c file from 3.17, and building it for 3.16 restores the use of tcq (debugged by adding a printk blk_rq_tagged + request->tag). So either uas is doing something wrong which happened to work in 3.16, or something has broken in 3.17. I've already added debug printk-s of scsi_device->tagged_supported, queue_depth, ordered_tags and simple_tags and those all look good (1, 29, 1, 1). I've also tried setting disable_blk_mq and that does not help. Any hints to help debugging this further (other then a bisect) are appreciated. If no-one has any smart ideas I guess I'll end up doing a full bisect. Regards, Hans