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| author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2022-07-21 20:41:10 +0300 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2022-07-26 21:56:49 +0300 |
| commit | 4f4179fcf420873002035cf1941d844c9e0e7cb3 (patch) | |
| tree | 35015628b89393bc881842cb1ccc2e381a315eeb /include/acpi/cppc_acpi.h | |
| parent | e0dccc3b76fb35bb257b4118367a883073d7390e (diff) | |
| download | linux-4f4179fcf420873002035cf1941d844c9e0e7cb3.tar.xz | |
ACPI: CPPC: Do not prevent CPPC from working in the future
There is a problem with the current revision checks in
is_cppc_supported() that they essentially prevent the CPPC support
from working if a new _CPC package format revision being a proper
superset of the v3 and only causing _CPC to return a package with more
entries (while retaining the types and meaning of the entries defined by
the v3) is introduced in the future and used by the platform firmware.
In that case, as long as the number of entries in the _CPC return
package is at least CPPC_V3_NUM_ENT, it should be perfectly fine to
use the v3 support code and disregard the additional package entries
added by the new package format revision.
For this reason, drop is_cppc_supported() altogether, put the revision
checks directly into acpi_cppc_processor_probe() so they are easier to
follow and rework them to take the case mentioned above into account.
Fixes: 4773e77cdc9b ("ACPI / CPPC: Add support for CPPC v3")
Cc: 4.18+ <stable@vger.kernel.org> # 4.18+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'include/acpi/cppc_acpi.h')
| -rw-r--r-- | include/acpi/cppc_acpi.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h index d389bab54241..f73d357ecdf5 100644 --- a/include/acpi/cppc_acpi.h +++ b/include/acpi/cppc_acpi.h @@ -17,7 +17,7 @@ #include <acpi/pcc.h> #include <acpi/processor.h> -/* Support CPPCv2 and CPPCv3 */ +/* CPPCv2 and CPPCv3 support */ #define CPPC_V2_REV 2 #define CPPC_V3_REV 3 #define CPPC_V2_NUM_ENT 21 |