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[PATCH v5 7/9] PCI/VGA: Replace vga_is_firmware_default() with a screen info check

Mario Limonciello posted 9 patches 3 months, 2 weeks ago
There is a newer version of this series
[PATCH v5 7/9] PCI/VGA: Replace vga_is_firmware_default() with a screen info check
Posted by Mario Limonciello 3 months, 2 weeks ago 
From: Mario Limonciello <mario.limonciello@amd.com>

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.

Suggested-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
v5:
 * split from next patch
---
 drivers/pci/vgaarb.c | 29 ++---------------------------
 1 file changed, 2 insertions(+), 27 deletions(-)

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index 78748e8d2dbae..c3457708c01e3 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -556,34 +556,9 @@ 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;
+	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 false;
+	return pdev == screen_info_pci_dev(si);
 }
 
 static bool vga_arb_integrated_gpu(struct device *dev)
-- 
2.43.0
Re: [PATCH v5 7/9] PCI/VGA: Replace vga_is_firmware_default() with a screen info check
Posted by Bjorn Helgaas 3 months, 1 week ago 
On Tue, Jun 24, 2025 at 03:30:40PM -0500, Mario Limonciello wrote:
> From: Mario Limonciello <mario.limonciello@amd.com>
> 
> 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.
> 
> Suggested-by: Thomas Zimmermann <tzimmermann@suse.de>
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

(after the kernel robot issue is fixed, of course)

> ---
> v5:
>  * split from next patch
> ---
>  drivers/pci/vgaarb.c | 29 ++---------------------------
>  1 file changed, 2 insertions(+), 27 deletions(-)
> 
> diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
> index 78748e8d2dbae..c3457708c01e3 100644
> --- a/drivers/pci/vgaarb.c
> +++ b/drivers/pci/vgaarb.c
> @@ -556,34 +556,9 @@ 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;
> +	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 false;
> +	return pdev == screen_info_pci_dev(si);
>  }
>  
>  static bool vga_arb_integrated_gpu(struct device *dev)
> -- 
> 2.43.0
>
Re: [PATCH v5 7/9] PCI/VGA: Replace vga_is_firmware_default() with a screen info check
Posted by kernel test robot 3 months, 2 weeks ago 
Hi Mario,

kernel test robot noticed the following build errors:

[auto build test ERROR on pci/next]
[also build test ERROR on pci/for-linus tiwai-sound/for-next tiwai-sound/for-linus tip/x86/core linus/master v6.16-rc3 next-20250625]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Mario-Limonciello/PCI-Add-helper-for-checking-if-a-PCI-device-is-a-display-controller/20250625-043200
base:   https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git next
patch link:    https://lore.kernel.org/r/20250624203042.1102346-8-superm1%40kernel.org
patch subject: [PATCH v5 7/9] PCI/VGA: Replace vga_is_firmware_default() with a screen info check
config: x86_64-defconfig (https://download.01.org/0day-ci/archive/20250625/202506251749.fPKnHMH5-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-12) 11.3.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250625/202506251749.fPKnHMH5-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202506251749.fPKnHMH5-lkp@intel.com/

All errors (new ones prefixed by >>):

   ld: vmlinux.o: in function `vga_arbiter_add_pci_device':
>> vgaarb.c:(.text+0x5f8f90): undefined reference to `screen_info_pci_dev'
>> ld: vgaarb.c:(.text+0x5f91f8): undefined reference to `screen_info_pci_dev'

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

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