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authorPrarit Bhargava <prarit@redhat.com>2018-01-18 10:09:51 -0500
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2018-02-07 11:39:58 +0100
commit0231d00082f61cfe03f2b7c27e5356f8cdf0312c (patch)
tree24f036cb972640ccdeed395a55d1c37571fcb3db /Documentation/admin-guide
parent890674343bb2d546825f713542b1e199f0728732 (diff)
ACPI: SPCR: Make SPCR available to x86
SPCR is currently only enabled or ARM64 and x86 can use SPCR to setup an early console. General fixes include updating Documentation & Kconfig (for x86), updating comments, and changing parse_spcr() to acpi_parse_spcr(), and earlycon_init_is_deferred to earlycon_acpi_spcr_enable to be more descriptive. On x86, many systems have a valid SPCR table but the table version is not 2 so the table version check must be a warning. On ARM64 when the kernel parameter earlycon is used both the early console and console are enabled. On x86, only the earlycon should be enabled by by default. Modify acpi_parse_spcr() to allow options for initializing the early console and console separately. Signed-off-by: Prarit Bhargava <prarit@redhat.com> Acked-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Mark Salter <msalter@redhat.com> Tested-by: Mark Salter <msalter@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'Documentation/admin-guide')
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt9
1 files changed, 6 insertions, 3 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 1bdcf572c2ac..aecb1c8ef675 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -917,9 +917,12 @@
earlycon= [KNL] Output early console device and options.
- When used with no options, the early console is
- determined by the stdout-path property in device
- tree's chosen node.
+ [ARM64] The early console is determined by the
+ stdout-path property in device tree's chosen node,
+ or determined by the ACPI SPCR table.
+
+ [X86] When used with no options the early console is
+ determined by the ACPI SPCR table.
cdns,<addr>[,options]
Start an early, polled-mode console on a Cadence