Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754073Ab2JHQeO (ORCPT ); Mon, 8 Oct 2012 12:34:14 -0400 Received: from mail-wi0-f178.google.com ([209.85.212.178]:60180 "EHLO mail-wi0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753851Ab2JHQeL (ORCPT ); Mon, 8 Oct 2012 12:34:11 -0400 MIME-Version: 1.0 X-Originating-IP: [116.14.92.167] In-Reply-To: References: Date: Tue, 9 Oct 2012 00:34:09 +0800 Message-ID: Subject: Re: [3.6-rc7] switcheroo race with Intel HDA... From: Daniel J Blueman To: Takashi Iwai Cc: Dave Airlie , Linux Kernel , alsa-devel@alsa-project.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2401 Lines: 58 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. Thanks, Daniel --- [1] snd_hda_intel 0000:00:1b.0: enabling device (0000 -> 0002) snd_hda_intel 0000:00:1b.0: irq 55 for MSI/MSI-X vga_switcheroo: enabled input: HDA Intel PCH Headphone as /devices/pci0000:00/0000:00:1b.0/sound/card0/input11 snd_hda_intel 0000:01:00.1: enabling device (0000 -> 0002) {echo IGD >/sys/kernel/debug/vgaswitcheroo/switch} {echo OFF >/sys/kernel/debug/vgaswitcheroo/switch} hda_intel: Disabling MSI hda-intel: 0000:01:00.1: Handle VGA-switcheroo audio client hda-intel: Disabling 0000:01:00.1 via VGA-switcheroo VGA switcheroo: switched nouveau off [drm] nouveau 0000:01:00.0: Disabling display... [drm] nouveau 0000:01:00.0: Disabling fbcon... [drm] nouveau 0000:01:00.0: Unpinning framebuffer(s)... [drm] nouveau 0000:01:00.0: Evicting buffers... [drm] nouveau 0000:01:00.0: Idling channels... [drm] nouveau 0000:01:00.0: Suspending GPU objects... [drm] nouveau 0000:01:00.0: And we're gone! hda-intel: spurious response 0x0:0x0, last cmd=0x1f0004 {repeats 220 times} hda-intel: spurious response 0x0:0x0, last cmd=0x1f0004 HDMI: failed to get afg sub nodes -- Daniel J Blueman -- 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/