VIA C3 Ezra-T has RevisionID equal to 1, but it needs RevisionKey to be 0
or CPU will ignore new frequency and will continue to work at old
frequency. New "revid_errata" option will force RevisionKey to be set to
0, whatever RevisionID is.
Additionaly "Longhaul" will not silently ignore unsuccessful transition.
It will try to check if "revid_errata" or "disable_acpi_c3" options need to
be enabled for this processor/system.
Same for Longhaul ver. 2 support. It will be disabled if none of above
options will work.
Best case scenario (with patch apllied and v2 enabled):
longhaul: VIA C3 'Ezra' [C5C] CPU detected. Longhaul v2 supported.
longhaul: Using northbridge support.
longhaul: VRM 8.5
longhaul: Max VID=1.350 Min VID=1.050, 13 possible voltage scales
longhaul: f: 300000 kHz, index: 0, vid: 1050 mV
[...]
longhaul: Voltage scaling enabled.
Worst case scenario:
longhaul: VIA C3 'Ezra-T' [C5M] CPU detected. Powersaver supported.
longhaul: Using northbridge support.
longhaul: Using ACPI support.
longhaul: VRM 8.5
longhaul: Claims to support voltage scaling but min & max are both 1.250. Voltage scaling disabled
longhaul: Failed to set requested frequency!
longhaul: Enabling "Ignore Revision ID" option.
longhaul: Failed to set requested frequency!
longhaul: Disabling ACPI C3 support.
longhaul: Disabling "Ignore Revision ID" option.
longhaul: Failed to set requested frequency!
longhaul: Enabling "Ignore Revision ID" option.
[akpm@linux-foundation.org: coding-style cleanups]
Signed-off-by: Rafal Bilski <rafalbilski@interia.pl>
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rafal Bilski