Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755206Ab2JIKEO (ORCPT ); Tue, 9 Oct 2012 06:04:14 -0400 Received: from cantor2.suse.de ([195.135.220.15]:36281 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754609Ab2JIKEK (ORCPT ); Tue, 9 Oct 2012 06:04:10 -0400 Date: Tue, 09 Oct 2012 12:04:08 +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: 3851 Lines: 114 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. Takashi --- diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c index f09ff6c..dcbfd29 100644 --- a/sound/pci/hda/hda_intel.c +++ b/sound/pci/hda/hda_intel.c @@ -501,6 +501,7 @@ struct azx { /* VGA-switcheroo setup */ unsigned int use_vga_switcheroo:1; + unsigned int vga_switcheroo_registered:1; unsigned int init_failed:1; /* delayed init failed */ unsigned int disabled:1; /* disabled by VGA-switcher */ @@ -2684,14 +2685,20 @@ static const struct vga_switcheroo_client_ops azx_vs_ops = { static int __devinit register_vga_switcheroo(struct azx *chip) { + int err; + if (!chip->use_vga_switcheroo) return 0; /* FIXME: currently only handling DIS controller * is there any machine with two switchable HDMI audio controllers? */ - return vga_switcheroo_register_audio_client(chip->pci, &azx_vs_ops, + err = vga_switcheroo_register_audio_client(chip->pci, &azx_vs_ops, VGA_SWITCHEROO_DIS, chip->bus != NULL); + if (err < 0) + return err; + chip->vga_switcheroo_registered = 1; + return 0; } #else #define init_vga_switcheroo(chip) /* NOP */ @@ -2713,7 +2720,8 @@ static int azx_free(struct azx *chip) if (use_vga_switcheroo(chip)) { if (chip->disabled && chip->bus) snd_hda_unlock_devices(chip->bus); - vga_switcheroo_unregister_client(chip->pci); + if (chip->vga_switcheroo_registered) + vga_switcheroo_unregister_client(chip->pci); } if (chip->initialized) { @@ -3067,14 +3075,6 @@ static int __devinit azx_create(struct snd_card *card, struct pci_dev *pci, } ok: - err = register_vga_switcheroo(chip); - if (err < 0) { - snd_printk(KERN_ERR SFX - "Error registering VGA-switcheroo client\n"); - azx_free(chip); - return err; - } - err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops); if (err < 0) { snd_printk(KERN_ERR SFX "Error creating device [card]!\n"); @@ -3345,6 +3345,13 @@ static int __devinit azx_probe(struct pci_dev *pci, if (pci_dev_run_wake(pci)) pm_runtime_put_noidle(&pci->dev); + err = register_vga_switcheroo(chip); + if (err < 0) { + snd_printk(KERN_ERR SFX + "Error registering VGA-switcheroo client\n"); + goto out_free; + } + dev++; return 0; -- 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/