From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934041AbcHNMDe (ORCPT ); Sun, 14 Aug 2016 08:03:34 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:45763 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932415AbcHNMDb (ORCPT ); Sun, 14 Aug 2016 08:03:31 -0400 Date: Sun, 14 Aug 2016 14:03:27 +0200 From: Pavel Machek To: Greg KH Cc: David Lang , Tom Yan , 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: <20160814120327.GA8292@amd> References: <20160813190340.GA29989@amd> <20160814092044.GA20392@amd> <20160814100102.GA31847@amd> <20160814112958.GA20778@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160814112958.GA20778@kroah.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi! > > > > 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? Yeah, USB order is known to be random. But root=/dev/sda (when sda is on SATA) is very old, and it would be good to keep it. > 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. Original reporter is me :-(. Yes, I can do bisect, if required. I'd like some kind of confirmation that it happens on other systems... Best regards, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html