[PATCH RESEND v1 1/2] ACPI/PCI: Make _SRS optional for link device

[Pierre Gondois]

From: Pierre Gondois <Pierre.Gondois@xxxxxxx>

In ACPI 6.4, s6.2.13 "_PRT (PCI Routing Table)", PCI legacy
interrupts can be described though a link device (first model).
>From s6.2.16 "_SRS (Set Resource Settings)":
"This optional control method [...]"

Make it optional to have a _SRS method for link devices.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215560
Signed-off-by: Pierre Gondois <pierre.gondois@xxxxxxx>
---
 drivers/acpi/pci_link.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
index 58647051c948..129e3e7e80ee 100644
--- a/drivers/acpi/pci_link.c
+++ b/drivers/acpi/pci_link.c
@@ -288,6 +288,13 @@ static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
 	if (!irq)
 		return -EINVAL;
 
+	if (!acpi_has_method(handle, METHOD_NAME__SRS)) {
+		if (link->irq.active == irq)
+			return 0;
+		acpi_handle_err(handle, "Unable to set IRQ %d: No _SRS.\n", irq);
+		return -ENODEV;
+	}
+
 	resource = kzalloc(sizeof(*resource) + 1, irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL);
 	if (!resource)
 		return -ENOMEM;
-- 
2.25.1