Re: [PATCH v3 3/3] ALSA: hda: Disabled unused audio controller for Dell platforms with Switchable Graphics

[Kai-Heng Feng]

at 6:59 PM, Pali RohÃr <pali.rohar@xxxxxxxxx> wrote:

> On Thursday 12 April 2018 12:50:02 Takashi Iwai wrote:
> > > +#if IS_ENABLED(CONFIG_DELL_LAPTOP)
> > > +static bool check_dell_switchable_gfx(struct pci_dev *pdev)
> > > +{
> > > +	bool (*dell_switchable_gfx_is_enabled_func)(void);
> > > +	bool enabled;
> > > +
> > > +	/* Only need to check for Dell laptops and AIOs */
> > > +	if (!dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Dell System", NULL) ||
> > > +	    !(dmi_match(DMI_CHASSIS_TYPE, "10") ||
> > > +	      dmi_match(DMI_CHASSIS_TYPE, "13")) ||
> > > +	    !(pdev->vendor == PCI_VENDOR_ID_ATI ||
> > > +	      pdev->vendor == PCI_VENDOR_ID_NVIDIA))
> > > +		return false;
> ...
> > > @@ -1711,6 +1745,11 @@ static int azx_create(struct snd_card *card,  
> > > struct pci_dev *pci,
> > >  	if (err < 0)
> > >  		return err;
> > >
> > > +	if (check_dell_switchable_gfx(pci)) {
> > > +		pci_disable_device(pci);
>
> Hi!
>
> Now looking at it again... This code disables all ATI and NVIDIA sound
> cards available in any Dell System (laptop or AIO) if system says that
> SG is enabled, right?

Yes.

> It means that also any external ATI or NVIDIA PCI card with audio device
> connected to Thunderbolt (e.g. via PCI <--> TB bridge) is always
> unconditionally disabled too?

I never thought of this case, thanks for bringing this up.
Do you have any suggestion to check if it connects to the system via  
Thunderbolt?

Kai-Heng

> > > +		return -ENODEV;
> > > +	}
>
> --
> Pali RohÃr
> pali.rohar@xxxxxxxxx