Re: [PATCH] PCI/VGA: Don't assume the only VGA device on a system is `boot_vga`

[Mario Limonciello <superm1@kernel.org>]

On 10/29/25 2:38 PM, Mario Limonciello wrote:
> +Thomas
> 
> On 10/29/25 2:34 PM, Bjorn Helgaas wrote:
>> On Wed, Oct 29, 2025 at 01:59:33PM -0500, Mario Limonciello (AMD) wrote:
>>> Some systems ship with multiple display class devices but not all
>>> of them are VGA devices. If the "only" VGA device on the system is not
>>> used for displaying the image on the screen marking it as `boot_vga`
>>> because nothing was found is totally wrong.
>>>
>>> This behavior actually leads to mistakes of the wrong device being
>>> advertised to userspace and then userspace can make incorrect decisions.
>>>
>>> As there is an accurate `boot_display` sysfs file stop lying about
>>> `boot_vga` by assuming if nothing is found it's the right device.
>>>
>>> Reported-by: Aaron Erhardt <aer@tuxedocomputers.com>
>>> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220712
>>> Tested-by: Aaron Erhardt <aer@tuxedocomputers.com>
>>> Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
>>
>> Do we need a Fixes: here?  A stable cc?
>>
>> The bugzilla suggests this might be a regression and hence v6.18
>> material?
> 
> Yeah I think you're right, we should add these two tags and this should 
> go to 6.18 if it's a reasonable change.
> 
> Cc: stable@vger.kernel.org
> Fixes: ad90860bd10ee ("fbcon: Use screen info to find primary device")
> 
> But let's also make sure Thomas Zimmermann agrees with this change.
> 

ping?

>>
>>> ---
>>>   drivers/pci/vgaarb.c | 7 -------
>>>   1 file changed, 7 deletions(-)
>>>
>>> diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
>>> index 436fa7f4c3873..baa242b140993 100644
>>> --- a/drivers/pci/vgaarb.c
>>> +++ b/drivers/pci/vgaarb.c
>>> @@ -652,13 +652,6 @@ static bool vga_is_boot_device(struct vga_device 
>>> *vgadev)
>>>           return true;
>>>       }
>>> -    /*
>>> -     * Vgadev has neither IO nor MEM enabled.  If we haven't found any
>>> -     * other VGA devices, it is the best candidate so far.
>>> -     */
>>> -    if (!boot_vga)
>>> -        return true;
>>> -
>>>       return false;
>>>   }
>>> -- 
>>> 2.43.0
>>>
> 
>