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[0/2] ACPI: Improve SPCR handling and messaging on SPCR-less systems

Message ID 20250606072802.191580-1-me@linux.beauty
Headers show
Series ACPI: Improve SPCR handling and messaging on SPCR-less systems | expand

Message

Li Chen June 6, 2025, 7:27 a.m. UTC 
From: Li Chen <chenl311@chinatelecom.cn>

This small series improves the kernel behavior and output when the ACPI SPCR
table is not present or not supported.

Currently, even on systems that completely lack an SPCR table, the kernel prints:
"Use ACPI SPCR as default console: Yes"

Or if with acpi=nospcr:
"Use ACPI SPCR as default console: No"

This may mislead users into thinking an SPCR table exists
when in fact there is no such table at all. This series addresses this in two steps:

Patch 1 ensures that acpi_parse_spcr() returns -ENODEV if CONFIG_ACPI_SPCR_TABLE is disabled.

Patch 2 updates arm64 acpi_boot_table_init() to only print the SPCR console message
if acpi_parse_spcr() succeeds.

This results in cleaner and more accurate boot logs on ARM64.

Tested on both SPCR-enabled and SPCR-less qemu-system arm64 virt platform. [1]

[1]: https://patchew.org/QEMU/20250528105404.457729-1-me@linux.beauty/

Li Chen (2):
  ACPI: Return -ENODEV from acpi_parse_spcr() when SPCR support is
    disabled
  ACPI: Suppress misleading SPCR console message when SPCR table is
    absent

 arch/arm64/kernel/acpi.c | 9 ++++++---
 include/linux/acpi.h     | 2 +-
 2 files changed, 7 insertions(+), 4 deletions(-)