Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752160AbbGMR4f (ORCPT ); Mon, 13 Jul 2015 13:56:35 -0400 Received: from mail-ig0-f174.google.com ([209.85.213.174]:33937 "EHLO mail-ig0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751834AbbGMR4d (ORCPT ); Mon, 13 Jul 2015 13:56:33 -0400 Date: Mon, 13 Jul 2015 12:56:07 -0500 From: Michael Welling To: Pali =?iso-8859-1?Q?Roh=E1r?= Cc: Sebastian Reichel , Tony Lindgren , Pavel Machek , Ivaylo Dimitrov , Aaro Koskinen , Nishanth Menon , linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: linux 4.2-rc1 broken Nokia N900 Message-ID: <20150713175607.GA6080@deathray> References: <201507111405.06048@pali> <20150713080920.GA25585@earth> <20150713170344.GA5825@deathray> <201507131909.06521@pali> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <201507131909.06521@pali> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5105 Lines: 114 On Mon, Jul 13, 2015 at 07:09:06PM +0200, Pali Roh?r wrote: > On Monday 13 July 2015 19:03:44 Michael Welling wrote: > > On Mon, Jul 13, 2015 at 10:09:21AM +0200, Sebastian Reichel wrote: > > > [+cc Michael Welling , author of all omap-spi > > > patches between 4.1 and 4.2-rc1] > > > > > > Hi, > > > > > > On Sun, Jul 12, 2015 at 11:44:25PM -0700, Tony Lindgren wrote: > > > > * Pali Roh?r [150711 05:07]: > > > > > Hello, > > > > > > > > > > now I tested 4.2-rc1 release on Nokia N900 and couple of > > > > > drivers are broken and cause kernel oops... > > > > > > > > > > Basically wifi, touchscreen and rtc drivers not working... > > > > > > > > > > Here are some relevant snippets form dmesg: > > > > > > > > > > [ 13.933959] Unhandled fault: external abort on non-linefetch > > > > > (0x1028) at 0xfa09802c [ 13.940490] pgd = cfb38000 > > > > > [ 13.946594] [fa09802c] *pgd=48011452(bad) > > > > > [ 13.952758] Internal error: : 1028 [#1] PREEMPT ARM > > > > > [ 13.958862] Modules linked in: tsc2005(+) omap_sham > > > > > twl4030_wdt omap_wdt [ 13.965332] CPU: 0 PID: 183 Comm: > > > > > modprobe Not tainted 4.2.0-rc1+ #363 [ 13.971801] Hardware > > > > > name: Nokia RX-51 board > > > > > [ 13.978302] task: cf572300 ti: cb1f2000 task.ti: cb1f2000 > > > > > [ 13.984924] PC is at omap2_mcspi_set_cs+0x44/0x4c > > > > Here is the disassembly of the omap2_mcspi_set_cs function from my > > compiler: 00000040 : > > 40: e2803e25 add r3, r0, #592 ; 0x250 > > 44: e5902258 ldr r2, [r0, #600] ; 0x258 > > 48: e1d330b2 ldrh r3, [r3, #2] > > 4c: e3130004 tst r3, #4 > > 50: 12211001 eorne r1, r1, #1 > > 54: e3520000 cmp r2, #0 > > 58: 012fff1e bxeq lr > > 5c: e5923018 ldr r3, [r2, #24] > > 60: e3510000 cmp r1, #0 > > 64: 13c33601 bicne r3, r3, #1048576 ; > > 0x100000 68: 03833601 orreq r3, r3, #1048576 ; > > 0x100000 6c: e5823018 str r3, [r2, #24] > > 70: e5902258 ldr r2, [r0, #600] ; 0x258 > > 74: e5922000 ldr r2, [r2] > > 78: e582302c str r3, [r2, #44] ; 0x2c > > 7c: e5903258 ldr r3, [r0, #600] ; 0x258 > > 80: e5933000 ldr r3, [r3] > > 84: e593202c ldr r2, [r3, #44] ; 0x2c > > 88: e12fff1e bx lr > > > > The omap2_mcspi_set_cs function is being called before the > > controller_state is initialized in omap2_mcspi_setup. > > > > That is why there is a conditional checking if controller_state is > > NULL. > > > > Perhaps the controller_state is uninitialized but has garbage instead > > of NULL causing the data abort. > > > > Though that does not make much sense because a similar check in the > > setup function did not cause a data abort in the past. > > > > Not sure what is going wrong here. > > > > Could you do a objdump with the compiler you are using? > > > > Hello, here is my objdump of 4.2-rc2 version: > > 00000064 : > 64: e3003182 movw r3, #386 ; 0x182 > 68: e19030b3 ldrh r3, [r0, r3] > 6c: e3130004 tst r3, #4 > 70: 0a000001 beq 7c > 74: e2711001 rsbs r1, r1, #1 > 78: 33a01000 movcc r1, #0 > 7c: e5902188 ldr r2, [r0, #392] ; 0x188 > 80: e3520000 cmp r2, #0 > 84: 012fff1e bxeq lr > 88: e5923018 ldr r3, [r2, #24] > 8c: e3510000 cmp r1, #0 > 90: 13c33601 bicne r3, r3, #1048576 ; 0x100000 > 94: 03833601 orreq r3, r3, #1048576 ; 0x100000 > 98: e5823018 str r3, [r2, #24] > 9c: e5902188 ldr r2, [r0, #392] ; 0x188 > a0: e5922000 ldr r2, [r2] > a4: e582302c str r3, [r2, #44] ; 0x2c > a8: e592302c ldr r3, [r2, #44] ; 0x2c > ac: e12fff1e bx lr 0x64+0x44 = 0xa8 That means that it got past the check for controller_state being NULL. So that means that controller_state is not NULL and not initialized properly causing the data abort. It still does not explain how the driver used to work given it initializes the controller_state in the setup function after doing the same check. Let me dig a little more. Wish I had a N900 to try this on. > > -- > Pali Roh?r > pali.rohar@gmail.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/