From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans de Goede Subject: [REGRESSION 3.17] scsi (uas) disks no longer using tagged command queuing Date: Tue, 09 Sep 2014 11:15:24 +0200 Message-ID: <540EC52C.3000804@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: 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 Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: linux-usb , SCSI development list , Linux Kernel Mailing List 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