From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964897AbcATUkl (ORCPT ); Wed, 20 Jan 2016 15:40:41 -0500 Received: from mail-ob0-f170.google.com ([209.85.214.170]:33401 "EHLO mail-ob0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752612AbcATUki (ORCPT ); Wed, 20 Jan 2016 15:40:38 -0500 Subject: Re: Boot problem on PPC with 4.4-git - Bisected to commit 21266be To: Dan Williams References: <569FE7A9.7090902@lwfinger.net> Cc: LKML From: Larry Finger Message-ID: <569FF0C3.5040103@lwfinger.net> Date: Wed, 20 Jan 2016 14:40:35 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/20/2016 02:16 PM, Dan Williams wrote: > On Wed, Jan 20, 2016 at 12:08 PM, Dan Williams wrote: >> On Wed, Jan 20, 2016 at 12:01 PM, Larry Finger >> wrote: >>> My PowerBook G4 Aluminum with a 32-bit PPC processor fails to boot for the >>> 4.4-git series. The problem was bisected to commit 21266be. It took a while >>> to figure out why a commit that only rearranges the Kconfig files could >>> cause the problem. >>> >>> The answer came when I read the commit message for 90a545e98126 and saw that >>> "Recompiling with CONFIG_IO_STRICT_DEVMEM=n" might be necessary. After I >>> made that change, the system boots. >>> >>> If it is the graphics hardware driver at fault, the VGA controller is listed >>> as an ATI RV350 [Mobility Radeon 9600 M10] with PCI ID 1002:4350. It uses >>> radeon as the driver. >>> >>> I'm not sure if this is a bug in the configuration, but I know that >>> selecting the default answer to all the new configuration parameters leaves >>> me with a machine that is unbootable. >> >> I agree that the default configuration should remain bootable. I'll >> send a change that does not force that default. >> >> Thanks for the report and sorry for the inconvenience. > > Are you sure that the bisect is pointing to "21266be9ed54 arch: > consolidate CONFIG_STRICT_DEVM in lib/Kconfig.debug" and not > "90a545e98126 restrict /dev/mem to idle io memory ranges"? The > default for CONFIG_STRICT_DEVM should be unchanged in 21266be9ed54, > it's not until 90a545e98126 that I would expect a behavior change. Yes. Commit 21266be9ed54 was the reported bad commit; however, the previous test kernel was 90a545e98126. In fact, I was struck that the final bisection build did not change any object files, thus you are right that 90a545e98126 is likely the bad commit. Larry