Hi Takashi, > On Sep 25, 2019, at 19:32, Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> wrote: > > 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. > > BugLink: https://bugs.launchpad.net/bugs/1840835 > Fixes: b516ea586d71 ("PCI: Enable NVIDIA HDA controllers") > Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> Do you still have any concern on this patch? Please merge [v5 1/2] and this patch [v4 2/2] if you think it's good. Thanks! Kai-Heng > --- > 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); > } > -- > 2.17.1 > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx https://mailman.alsa-project.org/mailman/listinfo/alsa-devel