Dne 10. 01. 20 v 10:56 Takashi Iwai napsal(a):

On Fri, 10 Jan 2020 10:43:26 +0100, Jaroslav Kysela wrote:

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Dne 18. 10. 19 v 9:38 Kai-Heng Feng napsal(a):

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Nvidia proprietary driver doesn't support runtime power management, so when a user only wants to use the integrated GPU, it's a common practice to let dGPU not to bind any driver, and let its upstream port to be runtime suspended. At the end of runtime suspension the port uses platform power management to disable power through _OFF method of power resource, which is listed by _PR3.

After commit b516ea586d71 ("PCI: Enable NVIDIA HDA controllers"), when the dGPU comes with an HDA function, the HDA won't be suspended if the dGPU is unbound, so the power resource can't be turned off by its upstream port driver.

Commit 37a3a98ef601 ("ALSA: hda - Enable runtime PM only for discrete GPU") only allows HDA to be runtime suspended once GPU is bound, to keep APU's HDA working.

However, HDA on dGPU isn't that useful if dGPU is not bound to any driver. So let's relax the runtime suspend requirement for dGPU's HDA function, to disable the power source to save lots of power.

This patch breaks the HDMI audio detection at least on some platforms (Lenovo P50 for example) with nouveau and the proprietary nvidia driver. Those laptops have the external HDMI/DP ports connected to dGPU instead the iGPU. The ACPI PR3 is set.

The runtime PM off fixes this problem:

echo on > /sys/bus/pci/devices/0000:01:00.1/power/control

But this will keep the power of the graphics chip on, and that's what the patch was supposed to "fix".

...

But I don't think that it's the best solution. My proposal is to create a pr3 check blacklist to keep power for the HDMI audio for those machines. Also we may add a new module parameter for snd-hda-intel to control this. Other ideas?

For nouveau, the best fix is to merge the audio component patch. This will make things working without fiddling with the power up/down. The patch has been pending over months under review in DRM side, unfortunately... Please pinging them for driving ahead.

Adding Cc: to dri-devel. You probably mean this thread:

https://lists.freedesktop.org/archives/dri-devel/2019-July/thread.html#22742...

For Nvidia, though, it's no path a binary-only stuff can go with, due to the GPL symbol of the component framework. Those guys know of it well, and they seem adding the temporary power up/down procedure by poking the proc file from the user-space side at the HDMI connection.

Wow.

About a module option: I don't think it's much better than the sysfs toggle. You can set up a simple udev rule if needed, too.

Ok, it's a bit nightmare to maintain those extra settings in the distribution.

Jaroslav

thanks,

Takashi

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			Jaroslav

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BugLink: https://bugs.launchpad.net/bugs/1840835 Fixes: b516ea586d71 ("PCI: Enable NVIDIA HDA controllers") Signed-off-by: Kai-Heng Feng kai.heng.feng@canonical.com

---

v5, v6:

• No change.

v4:

• Find upstream port, it's callee's responsibility now.

v3:

• Make changelog more clear.

v2:

• Change wording.
• Rebase to Tiwai's branch. sound/pci/hda/hda_intel.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c index 240f4ca76391..e63b871343e5 100644 --- a/sound/pci/hda/hda_intel.c +++ b/sound/pci/hda/hda_intel.c @@ -1280,11 +1280,17 @@ static void init_vga_switcheroo(struct azx *chip) { struct hda_intel *hda = container_of(chip, struct hda_intel, chip); struct pci_dev *p = get_bound_vga(chip->pci);

• struct pci_dev *parent; if (p) { dev_info(chip->card->dev, "Handle vga_switcheroo audio client\n"); hda->use_vga_switcheroo = 1;

• chip->bus.keep_power = 1; /* cleared in either gpu_bound op or codec probe */
  

• /* cleared in either gpu_bound op or codec probe, or when its
  

•  * upstream port has _PR3 (i.e. dGPU).
  

•  */
  

• parent = pci_upstream_bridge(p);
  

• chip->bus.keep_power = parent ? !pci_pr3_present(parent) : 1;
  chip->driver_caps |= AZX_DCAPS_PM_RUNTIME;
  pci_dev_put(p);
  

  }

-- Jaroslav Kysela perex@perex.cz Linux Sound Maintainer; ALSA Project; Red Hat, Inc.