On Thu, Mar 08, 2018 at 05:10:23PM +0800, 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! This should be fixed by the following series: https://lists.freedesktop.org/archives/dri-devel/2018-March/168012.html Please verify that by testing the series on the machine in question. I'm hoping to get those patches in for 4.17. I suspect that your patch may not be necessary then. > Since the discrete audio controller isn't useful when SG enabled, we > should just disable the device. I don't quite follow, when SG is enabled but hda_intel doesn't bind to the AMD audio device, how are you going to stream audio to external displays? Are external DP/HDMI ports muxed to the integrated GPU when SG is enabled? Thanks, Lukas > > Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> > --- > 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 <linux/clocksource.h> > #include <linux/time.h> > #include <linux/completion.h> > +#include <linux/dell-common.h> > > #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; > + > + 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); > -- > 2.15.1 > > _______________________________________________ > Alsa-devel mailing list > Alsa-devel@xxxxxxxxxxxxxxxx > http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
