From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Lutomirski Subject: Re: AAARGH bisection is hard (Re: [2.6.39 regression] X locks up hard right after logging in) Date: Fri, 13 May 2011 09:39:14 -0400 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, git@vger.kernel.org To: Linus Torvalds Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org [resend because the Android gmail client apparently generates HTML emails even for plain text] On Thu, May 12, 2011 at 1:37 PM, Linus Torvalds wrote: > On Thu, May 12, 2011 at 10:15 AM, Andrew Lutomirski wr= ote: >> >> OK, this sucks. =A0In the course of bisecting this, I've hit two oth= er >> apparently unrelated bugs that prevent my from testing large numbers >> of kernels. =A0Do I have two questions: >> >> 1. Anyone have any ideas from looking at the log? > > Nope, that doesn't look very helpful. > >> 2. =A0The !&$#@ bisection is skipping all over the place. =A0I've se= en >> 2.6.37 versions and all manner of -rc's out of order. > > That's the _point_ of bisection. It jumps around. You can start off > trying to pick points on my development tree, but I only have a > hundred merges or so. You're going to start delving into the actual > development versions very quickly. And if you don't do it early, > bisection is going to be much much slower, because it's not going to > pick half-way points. > > So bisection works so well exactly because it picks points that are > far away from each other, and you should just totally ignore the > version number. It's meaningless. Looking at it just confuses you. > Don't do it. > I actually had better results looking at the version number, saying "blech", and running git merge v2.6.38. (git bisect good gets a little confused if I feed it the merge result, but I can just lie.) Anyway, I must have made a mistake somewhere. The regression is in drm (presumably i915) and it has a new thread now. --Andy