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Commit 65ea8f2c authored by Mario Limonciello's avatar Mario Limonciello Committed by Rafael J. Wysocki
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ACPI: processor idle: Fix up C-state latency if not ordered

Generally, the C-state latency is provided by the _CST method or
FADT, but some OEM platforms using AMD Picasso, Renoir, Van Gogh,
and Cezanne set the C2 latency greater than C3's which causes the
C2 state to be skipped.

That will block the core entering PC6, which prevents S0ix working
properly on Linux systems.

In other operating systems, the latency values are not validated and
this does not cause problems by skipping states.

To avoid this issue on Linux, detect when latencies are not an
arithmetic progression and sort them.

Link: https://gitlab.freedesktop.org/agd5f/linux/-/commit/026d186e4592c1ee9c1cb44295912d0294508725
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/1230#note_712174


Suggested-by: default avatarPrike Liang <Prike.Liang@amd.com>
Suggested-by: default avatarAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: default avatarMario Limonciello <mario.limonciello@amd.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent d07f6ca9
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