diff mbox series

[v4,2/2] ALSA: hda: Allow HDA to be runtime suspended when dGPU is not bound to a driver

Message ID 20190925113255.25062-2-kai.heng.feng@canonical.com (mailing list archive)
State New, archived
Headers show
Series [v4,1/2] PCI: Add a helper to check Power Resource Requirements _PR3 existence | expand

Commit Message

Kai-Heng Feng Sept. 25, 2019, 11:32 a.m. UTC
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@canonical.com>
---
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(-)

Comments

Kai-Heng Feng Oct. 7, 2019, 6:49 p.m. UTC | #1
Hi Takashi,

> On Sep 25, 2019, at 19:32, Kai-Heng Feng <kai.heng.feng@canonical.com> 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@canonical.com>

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
>
Takashi Iwai Oct. 17, 2019, 7:19 a.m. UTC | #2
On Mon, 07 Oct 2019 20:49:56 +0200,
Kai-Heng Feng wrote:
> 
> Hi Takashi,
> 
> > On Sep 25, 2019, at 19:32, Kai-Heng Feng <kai.heng.feng@canonical.com> 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@canonical.com>
> 
> 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.

Sorry for the late reply, as I've been off for a few weeks.
Now I applied both patches for 5.4.


Thanks!

Takashi

> 
> 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
> > 
> 
>
diff mbox series

Patch

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);
 	}