On 7/22/25 10:33 AM, Bjorn Helgaas wrote:
On Tue, Jul 22, 2025 at 09:45:28AM -0500, Mario Limonciello wrote:
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.limoncie...@amd.com>
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).
I guess screen_info is actually *not* an x86 BIOS-ism, and on UEFI
systems, we do actually rely on UEFI, e.g., in efi_setup_gop(),
alloc_screen_info(), init_screen_info()?
Right. This all works because of the framebuffer allocated pre-boot and
reused by the kernel.
But this patch is x86-specific, so I'm guessing the same problem could
occur on arm64, Loongson, or other UEFI platforms, and this series
doesn't address those?
I've never seen a multi GPU solution on another architecture, but that
of course doesn't preclude one being created some day.
The series lays the groundwork that if it happens on another
architecture we can easily add an architecture specific solution for
those. If the solution is the same we could switch to a common helper.
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
