On Wed, 12 Aug 2026 14:22:06 +0200,
Andre Eikmeyer wrote:
>
> Hello everyone,
>
> The HDA controller normally needs different WAKEEN settings for runtime and
> system suspend, so azx_prepare() prevents direct complete. For a switcheroo
> audio client whose bound GPU is already runtime suspended and switched off,
> however, the controller is physically inaccessible and cannot signal wake
> events.
>
> Resuming the HDA function during system suspend also acquires its runtime
> PM supplier. This powers the discrete GPU back on only to suspend it again
> and can expose failures while restoring an otherwise unused GPU.
>
> Direct complete is now allowed when the bound VGA device is both runtime
> suspended and reported off by vga_switcheroo. Active GPUs and HDA
> controllers without a switcheroo binding retain the existing WAKEEN
> transition.
>
> This was tested as part of the MacBookPro15,1 hybrid graphics series on
> both the 2018 and 2019 revisions. The discrete GPU remains powered off
> across system suspend when it is unused, and suspend and resume complete
> successfully.
>
> Thank you for your time and consideration.
>
> Signed-off-by: Andre Eikmeyer <[email protected]>
Please drop greeting and thank-you texts. They can be put in the
cover letter, but not in each patch description.
About the code changes:
> +static bool azx_vga_is_powered_off(struct azx *chip)
> +{
> +#ifdef SUPPORT_VGA_SWITCHEROO
> + struct pci_dev *pci;
> + bool powered_off = false;
> +
> + if (!use_vga_switcheroo(container_of(chip, struct hda_intel, chip)))
> + return false;
> +
> + pci = get_bound_vga(chip->pci);
> + if (pci) {
> + powered_off = pm_runtime_suspended(&pci->dev) &&
> + vga_switcheroo_get_client_state(pci) ==
> VGA_SWITCHEROO_OFF;
> + pci_dev_put(pci);
> + }
> +
> + return powered_off;
> +#else
> + return false;
> +#endif
> +}
This ifdef can be moved to the caller side below...
> +
> static int azx_prepare(struct device *dev)
> {
> struct snd_card *card = dev_get_drvdata(dev);
> @@ -1025,6 +1048,10 @@ static int azx_prepare(struct device *dev)
> return 0;
>
> chip = card->private_data;
> + /* A powered-off dGPU cannot signal HDA wake events. */
> + if (azx_vga_is_powered_off(chip))
> + return 1;
> +
... to wrap the call site, instead. Since this is the only caller,
having the conditional here would make the intention clearer.
Also, a comment about what "return 1" plays here would be helpful for
readers. It's a small piece but has a significant meaning.
thanks,
Takashi
