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From:   Pierre Gondois <pierre.gondois@arm.com>
To:     linux-kernel@vger.kernel.org
Cc:     Pierre Gondois <Pierre.Gondois@arm.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Len Brown <lenb@kernel.org>, linux-pci@vger.kernel.org,
        linux-acpi@vger.kernel.org
Subject: [PATCH RESEND v1 1/2] ACPI/PCI: Make _SRS optional for link device
Date:   Fri,  1 Jul 2022 18:16:23 +0200
Message-Id: <20220701161624.2844305-2-pierre.gondois@arm.com>
In-Reply-To: <20220701161624.2844305-1-pierre.gondois@arm.com>
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From: Pierre Gondois <Pierre.Gondois@arm.com>

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@arm.com>
---
 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