linux-kernel - Re: [PATCH v10 2/4] PCI/VGA: Replace vga_is_firmware

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Message-ID: <1dd1dfe2-8005-4d02-8032-46c31c41423e@suse.de>
Date: Wed, 10 Sep 2025 16:33:29 +0200
From: Thomas Zimmermann <tzimmermann@...e.de>
To: "Mario Limonciello (AMD)" <superm1@...nel.org>,
 David Airlie <airlied@...il.com>, Bjorn Helgaas <bhelgaas@...gle.com>
Cc: Alex Deucher <alexander.deucher@....com>,
 Christian König <christian.koenig@....com>,
 Simona Vetter <simona@...ll.ch>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>,
 "open list:DRM DRIVERS" <dri-devel@...ts.freedesktop.org>,
 open list <linux-kernel@...r.kernel.org>,
 "open list:PCI SUBSYSTEM" <linux-pci@...r.kernel.org>,
 Daniel Dadap <ddadap@...dia.com>
Subject: Re: [PATCH v10 2/4] PCI/VGA: Replace vga_is_firmware_default() with a
 screen info check



Am 11.08.25 um 18:26 schrieb Mario Limonciello (AMD):
> vga_is_firmware_default() checks firmware resources to find the owner
> framebuffer resources to find the firmware PCI device.  This is an
> open coded implementation of screen_info_pci_dev().  Switch to using
> screen_info_pci_dev() instead.
>
> Acked-by: Bjorn Helgaas <bhelgaas@...gle.com>
> Suggested-by: Thomas Zimmermann <tzimmermann@...e.de>
> Signed-off-by: Mario Limonciello (AMD) <superm1@...nel.org>

Reviewed-by: Thomas Zimmermann <tzimmermann@...e.de>

> ---
> v10:
>   * Rebase on 6.17-rc1
> ---
>   drivers/pci/vgaarb.c | 31 +++++--------------------------
>   1 file changed, 5 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
> index 78748e8d2dbae..b58f94ee48916 100644
> --- a/drivers/pci/vgaarb.c
> +++ b/drivers/pci/vgaarb.c
> @@ -556,34 +556,13 @@ EXPORT_SYMBOL(vga_put);
>   
>   static bool vga_is_firmware_default(struct pci_dev *pdev)
>   {
> -#if defined(CONFIG_X86)
> -	u64 base = screen_info.lfb_base;
> -	u64 size = screen_info.lfb_size;
> -	struct resource *r;
> -	u64 limit;
> +#ifdef CONFIG_SCREEN_INFO
> +	struct screen_info *si = &screen_info;
>   
> -	/* Select the device owning the boot framebuffer if there is one */
> -
> -	if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
> -		base |= (u64)screen_info.ext_lfb_base << 32;
> -
> -	limit = base + size;
> -
> -	/* Does firmware framebuffer belong to us? */
> -	pci_dev_for_each_resource(pdev, r) {
> -		if (resource_type(r) != IORESOURCE_MEM)
> -			continue;
> -
> -		if (!r->start || !r->end)
> -			continue;
> -
> -		if (base < r->start || limit >= r->end)
> -			continue;
> -
> -		return true;
> -	}
> -#endif
> +	return pdev == screen_info_pci_dev(si);
> +#else
>   	return false;
> +#endif
>   }
>   
>   static bool vga_arb_integrated_gpu(struct device *dev)

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)