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Message-Id: <20220701161624.2844305-1-pierre.gondois@arm.com>
Date: Fri, 1 Jul 2022 18:16:22 +0200
From: Pierre Gondois <pierre.gondois@....com>
To: linux-kernel@...r.kernel.org
Cc: Bjorn Helgaas <bhelgaas@...gle.com>,
"Rafael J. Wysocki" <rafael@...nel.org>,
Len Brown <lenb@...nel.org>, linux-pci@...r.kernel.org,
linux-acpi@...r.kernel.org
Subject: [PATCH RESEND v1 0/2] Make _PRS and _SRS methods optional
The PCI legacy interrupts can be described with link devices,
cf ACPI 6.4, s6.2.13 "_PRT (PCI Routing Table)".
Link devices can have optional _SRS/_PRS methods to set the interrupt.
In PCI Firmware Specification Revision 3.3, s4.3.2.1. "Resource Setting":
"""
A non-configurable device only specifies _CRS. However, if they are
configurable, devices include _PRS to indicate the possible resource
setting and _SRS to allow OSPM to specify a new resource allocation
for the device.
"""
However, _PRS/_SRS methods are checked in drivers/acpi/pci_link.c,
and the driver aborts if they are absent.
E.g.: When _PRS is missing:
ACPI: \_SB_.PCI0.LNKA: _CRS 36 not found in _PRS
ACPI: \_SB_.PCI0.LNKA: No IRQ available. Try pci=noacpi or acpi=off
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215560
Pierre Gondois (2):
ACPI/PCI: Make _SRS optional for link device
ACPI/PCI: Make _PRS optional for link device
drivers/acpi/pci_link.c | 46 ++++++++++++++++++++++++++++-------------
1 file changed, 32 insertions(+), 14 deletions(-)
--
2.25.1
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