Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755320Ab2JIKH1 (ORCPT ); Tue, 9 Oct 2012 06:07:27 -0400 Received: from cantor2.suse.de ([195.135.220.15]:36370 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755272Ab2JIKHX (ORCPT ); Tue, 9 Oct 2012 06:07:23 -0400 Date: Tue, 09 Oct 2012 12:07:21 +0200 Message-ID: From: Takashi Iwai To: Daniel J Blueman Cc: Dave Airlie , Linux Kernel , alsa-devel@alsa-project.org Subject: Re: [3.6-rc7] switcheroo race with Intel HDA... In-Reply-To: References: User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/24.1 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2398 Lines: 64 At Tue, 09 Oct 2012 12:04:08 +0200, Takashi Iwai wrote: > > At Tue, 9 Oct 2012 00:34:09 +0800, > Daniel J Blueman wrote: > > > > On 8 October 2012 20:58, Takashi Iwai wrote: > > > At Tue, 25 Sep 2012 13:20:05 +0800, > > > Daniel J Blueman wrote: > > >> On my Macbook with a discrete Nvidia GPU, there is a race between > > >> selecting the integrated GPU and putting the discrete GPU into D3 [1], > > >> reliably causing a kernel oops [2]. > > >> > > >> Introducing a delay of ~1s between the calls prevents this. When the > > >> second 'OFF' write path executes, it looks like struct azx at > > >> card->private_data hasn't yet been allocated yet [3], so there is > > >> likely some locking missing. > > > > > > It's rather pci_get_drvdata() returning NULL (i.e. card is NULL, thus > > > card->private_data causes Oops). Could you check the patch like below > > > and see whether you get a kernel warning (but no Oops) or the problem > > > gets fixed by shifting the assignment of pci drvdata? > > [...] > > > > Good patching. Calling pci_set_drvdata later prevents the oops in HDA, > > though we see unexpected 0x0 responses in the response ring buffer > > [1], which we don't see when there's a >~1.5s delay between IGD and > > OFF. > > If the previous patch fixed, it means that the switching occurred > during the device was being probed. Maybe a better approach to > register the VGA switcheroo after the proper initialization. > > The patch below is a revised one. Please give it a try. Also, it's not clear which card spews the spurious response. Apply the patch below in addition. thanks, Takashi --- diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c index f09ff6c..9a0a29d 100644 --- a/sound/pci/hda/hda_intel.c +++ b/sound/pci/hda/hda_intel.c @@ -829,8 +829,9 @@ static void azx_update_rirb(struct azx *chip) smp_wmb(); chip->rirb.cmds[addr]--; } else - snd_printk(KERN_ERR SFX "spurious response %#x:%#x, " + snd_printk(KERN_ERR SFX "%s: spurious response %#x:%#x, " "last cmd=%#08x\n", + pci_name(chip->pci), res, res_ex, chip->last_cmd[addr]); } -- 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/