Re: 答复: 答复: [alsa-devel] 答复: [PATCH] vgaswitchroo: set audio client id according to bound gpu client id

[Takashi Iwai <tiwai-l3A5Bk7waGM@public.gmane.org>]

On Wed, 11 Jul 2018 10:41:38 +0200,
jimqu wrote:
> 
> 
> 
> On 2018年07月11日 15:19, Takashi Iwai wrote:
> > On Tue, 10 Jul 2018 13:21:00 +0200,
> > Takashi Iwai wrote:
> >>> revert the fix of amdgpu suspend issue, audio issue also can be observed.
> >> Did you check the behavior with the single AMD GPU hardware?
> >> If confirmed, we can forget about vga_switcheroo.
> > ... and taking a look back at the recent changes, I guess it can be
> > the forced runtime PM enablement, not directly with vga_switcheroo
> > action itself.
> 
> Yeah, the function vga_switcheroo_set_dynamic_switch() has discarded,
> so there is no way GFX driver to control audio power. However, keep in
> mind, current audio is bound to iGPU, that mean the issue should be
> nothing about
> vgaswtichreoo. since current audio pci bus is different from dGPU,
> that means the pci_bus_set_current_state() in
> vga_switcheroo_runtime_suspend() and pci_wakeup_bus() in
> vga_switcheroo_runtime_resume() could not touch the audio pci power
> state from dGPU instance.
> 
> This is a feedback got from our OEM developer, it is the overview of
> audio detect process.
> 
> > First, the kernel  audio driver will be triggered to read ELD, if the
> >> ELD is valid, it will report a jack event (on or available) to sound
> >> core driver; the pulseaudio subscribe all jack events, if it is told
> >> that the hdmi jack is plugged in (on), the pulseaudio will set this
> >> port to available, then the pa-card or pa-sink has available port, it
> >> can be selected (manually, some daemons or policy in
> >> /usr/share/pulseaudio/alsa-mixer/) as default output card/default sink.
> 
> If the description is correct. I think there are maybe two problems.
> 
> 1. audio will auto power off after setup device link duo to usage_count=0.
> 2. duo to audio is power down, it could not get the HDMI jack insert event.
> 
> How do you think?
> 
> > Jim, could you tell me which PCI devices are handled as vga_switcheroo
> > audio client?  The kernel should show all messages "xxx: Handle
> > vga_switcheroo audio client".
> 
> [    4.311095] snd_hda_intel 0000:06:00.1: enabling device (0000 -> 0002)
> [    4.314286] snd_hda_intel 0000:06:00.1: Handle vga_switcheroo audio
> client
> [    4.314822] snd_hda_intel 0000:06:00.6: enabling device (0000 -> 0002)
> 
> 01:00.0 VGA compatible controller [0300]: Advanced Micro Devices,
> Inc. [AMD/ATI] Device [1002:699f] (rev c3)
> 06:00.0 VGA compatible controller [0300]: Advanced Micro Devices,
> Inc. [AMD/ATI] Device [1002:15dd] (rev d1)
> 06:00.1 Audio device [0403]: Advanced Micro Devices, Inc. [AMD/ATI]
> Device [1002:15de]

OK this sheds a brighter light, finally.

If my understanding is correct, the issue is a false vga_switcheroo
audio detection, after all.  This is the primary GPU and it shouldn't
be registered as a vga_switcheroo discrete GPU.

Below is a very ugly workaround for this particular case.  It assumes
that the AMD+AMD combo will never have audio outputs on both but only
for the primary, and it's possibly wrong.

Is there a handy way to identify whether the given VGA PCI entry is
a discrete GPU or not?  The amdgpu and radeon seem checking ATPX
ACPI.


Takashi

---
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -1418,8 +1418,18 @@ static int azx_dev_free(struct snd_device *device)
  */
 static struct pci_dev *get_bound_vga(struct pci_dev *pci)
 {
+	static const struct pci_device_id ids[] = {
+		{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_ANY_ID),
+		  .class = PCI_BASE_CLASS_DISPLAY << 16,
+		  .class_mask = 0xff << 16 },
+		{}
+	};
 	struct pci_dev *p;
 
+	/* check whether Intel graphics is present as primary GPU */
+	if (!pci_dev_present(ids))
+		return NULL;
+
 	/* check only discrete GPU */
 	switch (pci->vendor) {
 	case PCI_VENDOR_ID_ATI:
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