Re: [PATCH v9 8/9] fbcon: Use screen info to find primary device

[Mario Limonciello]

On 7/22/25 9:38 AM, Bjorn Helgaas wrote:
> On Thu, Jul 17, 2025 at 12:38:11PM -0500, Mario Limonciello wrote:
> > From: Mario Limonciello <mario.limonciello@xxxxxxx>
> >
> > On systems with non VGA GPUs fbcon can't find the primary GPU because
> > video_is_primary_device() only checks the VGA arbiter.
> >
> > Add a screen info check to video_is_primary_device() so that callers
> > can get accurate data on such systems.
>
> This relies on screen_info, which I think is an x86 BIOS-ism.  Isn't
> there a UEFI console path?  How does that compare with this?  Is that
> relevant or is it something completely different?

When I created and tested this I actually did this on a UEFI system 
(which provides a UEFI GOP driver).
 >
> >   bool video_is_primary_device(struct device *dev)
> >   {
> > +#ifdef CONFIG_SCREEN_INFO
> > +	struct screen_info *si = &screen_info;
> > +#endif
> >   	struct pci_dev *pdev;
> >   
> >   	if (!dev_is_pci(dev))
> > @@ -34,7 +38,18 @@ bool video_is_primary_device(struct device *dev)
> >   
> >   	pdev = to_pci_dev(dev);
> >   
> > -	return (pdev == vga_default_device());
> > +	if (!pci_is_display(pdev))
> > +		return false;
> > +
> > +	if (pdev == vga_default_device())
> > +		return true;
> > +
> > +#ifdef CONFIG_SCREEN_INFO
> > +	if (pdev == screen_info_pci_dev(si))
> > +		return true;
> > +#endif
> > +
> > +	return false;
> >   }
> >   EXPORT_SYMBOL(video_is_primary_device);
> >   
> > --
> > 2.43.0