lkml.org 
[lkml]   [2022]   [Jul]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Subject[PATCH RESEND v1 0/2] Make _PRS and _SRS methods optional
Date
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

\
 
 \ /
  Last update: 2022-07-01 18:19    [W:0.064 / U:0.684 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site