Hi
Am 29.10.26 um 04:34 schrieb [email protected]:
From: wuqianhai <[email protected]>
On LoongArch, PCI resource assignment completes during subsys_initcall
(acpi_init), before vga_arb_device_init() runs. By that time the
firmware framebuffer BAR may already have been relocated, leaving
screen_info's lfb_base stale. Enable vga_is_firmware_default() for
LoongArch and refresh screen_info in vga_arb_device_init() before the
boot device is matched.
Unlike x86, sysfb_primary_display is only defined when CONFIG_SYSFB is
enabled on LoongArch, so have VGA_ARB select SYSFB there.
Signed-off-by: wuqianhai <[email protected]>
---
Changes in v2:
- Add VGA_ARB's select of SYSFB for LoongArch to avoid an undefined
reference when CONFIG_SCREEN_INFO is not set.
- Restrict the screen_info_apply_fixups() call to CONFIG_LOONGARCH so
x86 and other architectures are unaffected.
- Enable vga_is_firmware_default() for LoongArch.
---
drivers/pci/Kconfig | 1 +
drivers/pci/vgaarb.c | 12 +++++++++++-
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index 0c7408509ba2..55cc60f5d312 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -256,6 +256,7 @@ config VGA_ARB
default y
depends on !S390
select SCREEN_INFO if X86
+ select SYSFB if LOONGARCH
help
Some "legacy" VGA devices implemented on PCI typically have the same
hard-decoded addresses as they did on ISA. When multiple PCI devices
diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index 3e58b2c05c85..1b7e915629f9 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -566,7 +566,7 @@ EXPORT_SYMBOL(vga_put);
static bool vga_is_firmware_default(struct pci_dev *pdev)
{
-#if defined CONFIG_X86
+#if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH)
return pdev == screen_info_pci_dev(&sysfb_primary_display.screen);
#else
return false;
@@ -1527,6 +1527,16 @@ static int __init vga_arb_device_init(void)
int rc;
struct pci_dev *pdev;
+#if defined(CONFIG_LOONGARCH)
+ /*
+ * On LoongArch, PCI resource assignment completes during
+ * subsys_initcall (acpi_init), before the VGA arbiter runs. Refresh
+ * screen_info so vga_is_firmware_default() can match the relocated
+ * BAR.
+ */
+ screen_info_apply_fixups();
+#endif
No per-arch defines in generic code. All the setup should work the same
on all architectures. All global screen-info state should be maintained
by drivers/firmware/sysfb.c. Otherwise the framebuffer setup gets even
more convoluted than it already is.
My question is why does vga_is_firmware_default() run before
sysfb_init()? [1] Does acpi_init call into it? [1]
https://elixir.bootlin.com/linux/v7.3/source/drivers/firmware/sysfb.c#L225
Apart from that, we can decouple screen_info_apply_fixups() from
sysfb_init(). After relocation happens, the PCI code could call the
helper directly and let it update the global screen_info.
Best regards
Thomas
+
rc = misc_register(&vga_arb_device);
if (rc < 0)
pr_err("error %d registering device\n", rc);
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Stefan Gaiser, Jochen Jaser, Abhinav Puri, (HRB 36809, AG Nürnberg)
