summaryrefslogtreecommitdiff
path: root/drivers/acpi/cppc_acpi.c (follow)
Commit message (Collapse)AuthorAge
* ACPI / CPPC: do not require the _PSD methodAl Stone2019-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 4c4cdc4c63853fee48c02e25c8605fb65a6c9924 ] According to the ACPI 6.3 specification, the _PSD method is optional when using CPPC. The underlying assumption is that each CPU can change frequency independently from all other CPUs; _PSD is provided to tell the OS that some processors can NOT do that. However, the acpi_get_psd() function returns ENODEV if there is no _PSD method present, or an ACPI error status if an error occurs when evaluating _PSD, if present. This makes _PSD mandatory when using CPPC, in violation of the specification, and only on Linux. This has forced some firmware writers to provide a dummy _PSD, even though it is irrelevant, but only because Linux requires it; other OSPMs follow the spec. We really do not want to have OS specific ACPI tables, though. So, correct acpi_get_psd() so that it does not return an error if there is no _PSD method present, but does return a failure when the method can not be executed properly. This allows _PSD to be optional as it should be. Signed-off-by: Al Stone <ahs3@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
* ACPI / CPPC: Prevent cpc_desc_ptr points to the invalid dataHoan Tran2016-09-07
| | | | | | | | | | | | | | | | commit 2324d15447a9db168b1f85e3feac635b1ff8edb8 upstream. When CPPC fails to request a PCC channel, the CPC data is freed and cpc_desc_ptr points to the invalid data. Avoid this issue by moving the cpc_desc_ptr assignment after the PCC channel request. Signed-off-by: Hoan Tran <hotran@apm.com> Acked-by: Ashwin Chaugule <ashwin.chaugule@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ACPI: CPPC: Return error if _CPC is invalid on a CPUHoan Tran2016-09-07
| | | | | | | | | | | | | | | commit 8343c40d3de32ebfe8f48b043964e4ba0e7701f7 upstream. Based on 8.4.7.1 section of ACPI 6.1 specification, if the platform supports CPPC, the _CPC object must exist under all processor objects. If cpc_desc_ptr pointer is invalid on any CPUs, acpi_get_psd_map() should return error and CPPC cpufreq driver can not be registered. Signed-off-by: Hoan Tran <hotran@apm.com> Reviewed-by: Prashanth Prakash <pprakash@codeaurora.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge branches 'pm-cpufreq' and 'acpi-cppc'Rafael J. Wysocki2015-11-20
|\ | | | | | | | | | | | | | | | | | | | | | | | | * pm-cpufreq: Revert "Documentation: kernel_parameters for Intel P state driver" cpufreq: mediatek: fix build error cpufreq: intel_pstate: Add separate support for Airmont cores cpufreq: intel_pstate: Replace BYT with ATOM Revert "cpufreq: intel_pstate: Use ACPI perf configuration" Revert "cpufreq: intel_pstate: Avoid calculation for max/min" * acpi-cppc: ACPI / CPPC: Use h/w reduced version of the PCCT structure
| * ACPI / CPPC: Use h/w reduced version of the PCCT structureAshwin Chaugule2015-11-14
| | | | | | | | | | | | | | | | | | | | CPPC is enabled only on platforms which support the h/w reduced ACPI specification, so use the h/w reduced version of the PCCT consistently when deferencing PCCT contents. Fixes: 337aadff8e45 (ACPI: Introduce CPU performance controls using CPPC) Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* | ACPI / CPPC: Fix potential memory leakAshwin Chaugule2015-10-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 337aadff8e45 (ACPI: Introduce CPU performance controls using CPPC) leads to the following static checker warning: drivers/acpi/cppc_acpi.c:527 acpi_cppc_processor_probe() warn: overwrite may leak 'cpc_ptr' Fix the warning by removing the bogus per-CPU pointer dereference. Fixes: 337aadff8e45 (ACPI: Introduce CPU performance controls using CPPC) Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* | ACPI / CPPC: signedness bug in register_pcc_channel()Dan Carpenter2015-10-26
|/ | | | | | | | | | The "pcc_subspace_idx" is -1 if it hasn't been initialized yet. We need it to be signed. Fixes: 337aadff8e45 (ACPI: Introduce CPU performance controls using CPPC) Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Acked-by: Ashwin Chaugule <ashwin.chaugule@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* ACPI: Introduce CPU performance controls using CPPCAshwin Chaugule2015-10-12
CPPC stands for Collaborative Processor Performance Controls and is defined in the ACPI v5.0+ spec. It describes CPU performance controls on an abstract and continuous scale allowing the platform (e.g. remote power processor) to flexibly optimize CPU performance with its knowledge of power budgets and other architecture specific knowledge. This patch adds a shim which exports commonly used functions to get and set CPPC specific controls for each CPU. This enables CPUFreq drivers to gather per CPU performance data and use with exisiting governors or even allows for customized governors which are implemented inside CPUFreq drivers. Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org> Reviewed-by: Al Stone <al.stone@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>