diff options
| author | Prarit Bhargava <prarit@redhat.com> | 2018-01-18 10:09:51 -0500 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2018-02-07 11:39:58 +0100 |
| commit | 0231d00082f61cfe03f2b7c27e5356f8cdf0312c (patch) | |
| tree | 24f036cb972640ccdeed395a55d1c37571fcb3db /Documentation/admin-guide | |
| parent | 890674343bb2d546825f713542b1e199f0728732 (diff) | |
| download | lwn-0231d00082f61cfe03f2b7c27e5356f8cdf0312c.tar.gz lwn-0231d00082f61cfe03f2b7c27e5356f8cdf0312c.zip | |
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.txt | 9 |
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 |