From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753368AbcHNL3x (ORCPT ); Sun, 14 Aug 2016 07:29:53 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:40578 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933884AbcHNL3u (ORCPT ); Sun, 14 Aug 2016 07:29:50 -0400 Date: Sun, 14 Aug 2016 13:29:58 +0200 From: Greg KH To: David Lang Cc: Tom Yan , Pavel Machek , kernel list , james harvey , regressions@leemhuis.info, hdegoede@redhat.com, Tejun Heo , linux-ide@vger.kernel.org, linux-usb@vger.kernel.org, Oliver Neukum , Alan Stern Subject: Re: Regression - SATA disks behind USB ones on v4.8-rc1, breaking boot. [Re: Who reordered my disks (probably v4.8-rc1 problem)] Message-ID: <20160814112958.GA20778@kroah.com> References: <20160813190340.GA29989@amd> <20160814092044.GA20392@amd> <20160814100102.GA31847@amd> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.6.2 (2016-07-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Aug 14, 2016 at 03:26:45AM -0700, David Lang wrote: > On Sun, 14 Aug 2016, Tom Yan wrote: > > > On 14 August 2016 at 18:07, Tom Yan wrote: > > > On 14 August 2016 at 18:01, Pavel Machek wrote: > > > > > > > > Since SATA support was merged, certainly since v2.4, and from way > > > > before /dev/disk/by-id existed. > > > > > > I have no idea how "SATA before USB" had been done in the past (if it > > > was ever a thing in the kernel), but that has not been the case since > > > at least v3.0 AFAIR. > > > > > > > > > > > People may not run udev, and you can't use /dev/disk/by-id on kernel > > > > command line. > > > > > > > > > > No, but you can always use root=PARTUUID=, that's built into the > > > kernel. (root=UUID= requires udev or so though). > > > > Silly me. root=UUID= has nothing to do with udev, but `blkid` in > > util-linux. At least that's how it's done in Arch/mkinitcpio. > > > > The rule is "don't break working systems", not "but we are allowed to break > systems, see it says here not to depend on this" > > Drive ordering has been stable since the 0.1 kernel [1] Drive probing order of USB has always been non-deterministic, so while I agree that it is not good to break existing systems at all, perhaps this is on the edge of what works vs. doesn't work? I know my USB drives always seem to come up in random order, which is why tools like udev were invented :) > It takes a lot longer to detect USB drives, why in the world would they be > detected before hard-wired drives? Depends, some hard-wired drives take much longer to find than USB ones. That being said, it would be great if the original reporter could use 'git bisect' and let the linux-usb and linux-scsi mailing list know what the offending patch is, and we can take it from there. thanks, greg k-h