From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751235AbeCIJCb (ORCPT ); Fri, 9 Mar 2018 04:02:31 -0500 Received: from mail-wm0-f65.google.com ([74.125.82.65]:36056 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750883AbeCIJC1 (ORCPT ); Fri, 9 Mar 2018 04:02:27 -0500 X-Google-Smtp-Source: AG47ELtigiIPQU/aSWCBb/fM6VYWXxQxF+Oebz66va2Xce/+Myq4LtpWr+BdRYlGft30d29o+KNE1A== Date: Fri, 9 Mar 2018 10:02:23 +0100 From: Pali =?utf-8?B?Um9ow6Fy?= To: Kai-Heng Feng Cc: mjg59@srcf.ucam.org, dvhart@infradead.org, andy@infradead.org, mario.limonciello@dell.com, tiwai@suse.com, platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, alsa-devel@alsa-project.org Subject: Re: [PATCH v2 3/3] ALSA: hda: Disabled unused audio controller for Dell platforms with Switchable Graphics Message-ID: <20180309090223.xb55ltac4pfesdrh@pali> References: <20180308091023.9061-1-kai.heng.feng@canonical.com> <20180308091023.9061-3-kai.heng.feng@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20180308091023.9061-3-kai.heng.feng@canonical.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 08 March 2018 17:10:23 Kai-Heng Feng wrote: > Some Dell platforms (Preicsion 7510/7710/7520/7720) have a BIOS option > "Switchable Graphics" (SG). > > When SG is enabled, we have: > 00:02.0 VGA compatible controller: Intel Corporation Device 591b (rev 04) > 00:1f.3 Audio device: Intel Corporation CM238 HD Audio Controller (rev 31) > 01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Ellesmere [Polaris10] > 01:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Ellesmere [Radeon RX 580] > > The Intel Audio outputs all the sound, including HDMI audio. The audio > controller comes with AMD graphics doesn't get used. > > When SG is disabled, we have: > 00:1f.3 Audio device: Intel Corporation CM238 HD Audio Controller (rev 31) > 01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Ellesmere [Polaris10] > 01:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Ellesmere [Radeon RX 580] > > Now it's a typical discrete-only system. HDMI audio comes from AMD audio > controller, others from Intel audio controller. > > When SG is enabled, the unused AMD audio controller still exposes its > sysfs, so userspace still opens the control file and stream. If > userspace tries to output sound through the stream, it hangs when > runtime suspend kicks in: > [ 12.796265] snd_hda_intel 0000:01:00.1: Disabling via vga_switcheroo > [ 12.796367] snd_hda_intel 0000:01:00.1: Cannot lock devices! > > Since the discrete audio controller isn't useful when SG enabled, we > should just disable the device. > > Signed-off-by: Kai-Heng Feng > --- > v2: Mario suggested to squash the HDA part into the same series. > > sound/pci/hda/hda_intel.c | 35 +++++++++++++++++++++++++++++++++++ > 1 file changed, 35 insertions(+) > > diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c > index 96143df19b21..8e3e8b88624a 100644 > --- a/sound/pci/hda/hda_intel.c > +++ b/sound/pci/hda/hda_intel.c > @@ -49,6 +49,7 @@ > #include > #include > #include > +#include > > #ifdef CONFIG_X86 > /* for snoop control */ > @@ -1620,6 +1621,35 @@ static void check_msi(struct azx *chip) > } > } > > +#if IS_ENABLED(CONFIG_DELL_LAPTOP) > +static bool check_dell_switchable_gfx(struct pci_dev *pdev) > +{ > + static int (*dell_switchable_gfx_enabled_func)(bool *); > + bool enabled; > + int err; > + > + if (pdev->vendor != PCI_VENDOR_ID_ATI || > + pdev->subsystem_vendor != PCI_VENDOR_ID_DELL) > + return false; Are you sure that you want to do this check unconditionally on all machines which have enabled CONFIG_DELL_LAPTOP? Subvendor ID_DELL for dell specific code is not suspicious, but ID_ATI is. What would happen if ATI vendor changes to NVIDIA or other which is not related to Dell? Interesting question would be, how handle this situation Windows? > + dell_switchable_gfx_enabled_func = > + symbol_request(dell_switchable_gfx_enabled); > + if (!dell_switchable_gfx_enabled_func) > + return false; > + > + err = dell_switchable_gfx_enabled_func(&enabled); > + > + symbol_put(dell_switchable_gfx_enabled); > + > + return !err ? enabled : false; > +} > +#else > +static bool check_dell_switchable_gfx(struct pci_dev *pdev) > +{ > + return false; > +} > +#endif > + > /* check the snoop mode availability */ > static void azx_check_snoop_available(struct azx *chip) > { > @@ -1702,6 +1732,11 @@ static int azx_create(struct snd_card *card, struct pci_dev *pci, > if (err < 0) > return err; > > + if (check_dell_switchable_gfx(pci)) { > + pci_disable_device(pci); > + return -ENODEV; > + } > + > hda = kzalloc(sizeof(*hda), GFP_KERNEL); > if (!hda) { > pci_disable_device(pci); -- Pali Rohár pali.rohar@gmail.com