From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753467Ab1ABMNV (ORCPT ); Sun, 2 Jan 2011 07:13:21 -0500 Received: from astoria.ccjclearline.com ([64.235.106.9]:38145 "EHLO astoria.ccjclearline.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751283Ab1ABMNU (ORCPT ); Sun, 2 Jan 2011 07:13:20 -0500 Date: Sun, 2 Jan 2011 07:13:11 -0500 (EST) From: "Robert P. J. Day" X-X-Sender: rpjday@localhost6.localdomain6 To: Maxim Levitsky cc: Anca Emanuel , Ubuntu kernel team mailing list , LKML , "intel-gfx@lists.freedesktop.org" Subject: Re: is there a fix for ubuntu with intel GPU booting to blank screen? In-Reply-To: <1293832014.27359.7.camel@maxim-laptop> Message-ID: References: <1293814089.6993.4.camel@maxim-laptop> <1293832014.27359.7.camel@maxim-laptop> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - astoria.ccjclearline.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - crashcourse.ca X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 31 Dec 2010, Maxim Levitsky wrote: > On Fri, 2010-12-31 at 12:01 -0500, Robert P. J. Day wrote: > > On Fri, 31 Dec 2010, Maxim Levitsky wrote: > > > > ... snip related to i915 blank screen issues ... > > > > > Since you know how to compile kernel, and even have a close working > > > version, you really should just bisect the bug. > > > > > > Bisection is a built-in in the git binary search that allows you to > > > find the first commit that introduced the bug. > > > > > > For example, quick google gives, > > > http://www.kernel.org/pub/software/scm/git-core/docs/v1.0.13/howto/isolate-bugs-with-bisect.txt > > > > oh, i know how to do bisection but, to be frank, i just don't have > > the time. i'm under a brutal deadline for some billable work and, > > even if i had the time, i suspect that when i eventually tracked down > > the commit, i probably wouldn't really appreciate what i was looking > > at, anyway. > You truly underestimate this. Having commit that broke things points > perfectly at the issue. Then, developers can even just revert the > offending commit until it is understood why it breaks stuff. i suspect what i'm about to type won't come as a surprise to anyone currently working on this problem, but there is a cheap workaround to boot to the command line using one of the offending kernels. when i boot, say, 2.6.37-rc8+ (or any other kernel, for that matter), the first two lines i always see are (paraphrasing): /dev/pts busy ... ureadahead info ... and that's it, just those two lines. it's the same no matter which kernel i boot. and here's where things differ. for a properly functioning kernel, the display then switches to hi-res mode, the two lines are redisplayed in a smaller font and the boot continues normally, right up to the desktop (say, with my 2.6.37-rc5+ kernel). for a bad kernel (say, my 2.6.37-rc8+), it's that switch to hi-res after those original two lines of output where the display goes black and stays that way so it looks like a KMS-related problem. a workaround to at least let me boot to the command line is to add "i915.modeset=0" as a kernel parm, but that won't then let me start X once i'm up and running. there are all sorts of reports of this type of behaviour, like this: https://bbs.archlinux.org/viewtopic.php?id=96759 which is where i got the idea to use that kernel parm and the behaviour i saw matches exactly what's in that post. in any event, as i reported, this is still happening with -rc8. rday -- ======================================================================== Robert P. J. Day Waterloo, Ontario, CANADA http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday ========================================================================