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Dynamic BIOS SAR driver exposing dynamic SAR information from BIOS The Dynamic SAR (Specific Absorption Rate) driver uses ACPI DSM (Device Specific Method) to communicate with BIOS and retrieve dynamic SAR information and change notifications. The driver uses sysfs to expose this data to userspace via read and notify. Sysfs interface is documented in detail under: Documentation/ABI/testing/sysfs-driver-intc_sar Signed-off-by: Shravan S <s.shravan@intel.com> Link: https://lore.kernel.org/r/20210723211452.27995-2-s.shravan@intel.com Reviewed-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
55 lines
2 KiB
Plaintext
55 lines
2 KiB
Plaintext
What: /sys/bus/platform/devices/INTC1092:00/intc_reg
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Date: August 2021
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KernelVersion: 5.15
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Contact: Shravan S <s.shravan@intel.com>,
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An Sudhakar <sudhakar.an@intel.com>
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Description:
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Specific Absorption Rate (SAR) regulatory mode is typically
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derived based on information like mcc (Mobile Country Code) and
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mnc (Mobile Network Code) that is available for the currently
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attached LTE network. A userspace application is required to set
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the current SAR regulatory mode on the Dynamic SAR driver using
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this sysfs node. Such an application can also read back using
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this sysfs node, the currently configured regulatory mode value
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from the Dynamic SAR driver.
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Acceptable regulatory modes are:
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== ====
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0 FCC
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1 CE
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2 ISED
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== ====
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- The regulatory mode value has one of the above values.
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- The default regulatory mode used in the driver is 0.
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What: /sys/bus/platform/devices/INTC1092:00/intc_data
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Date: August 2021
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KernelVersion: 5.15
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Contact: Shravan S <s.shravan@intel.com>,
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An Sudhakar <sudhakar.an@intel.com>
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Description:
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This sysfs entry is used to retrieve Dynamic SAR information
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emitted/maintained by a BIOS that supports Dynamic SAR.
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The retrieved information is in the order given below:
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- device_mode
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- bandtable_index
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- antennatable_index
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- sartable_index
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The above information is sent as integer values separated
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by a single space. This information can then be pushed to a
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WWAN modem that uses this to control the transmit signal
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level using the Band/Antenna/SAR table index information.
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These parameters are derived/decided by aggregating
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device-mode like laptop/tablet/clamshell etc. and the
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proximity-sensor data available to the embedded controller on
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given host. The regulatory mode configured on Dynamic SAR
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driver also influences these values.
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The userspace applications can poll for changes to this file
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using POLLPRI event on file-descriptor (fd) obtained by opening
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this sysfs entry. Application can then read this information from
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the sysfs node and consume the given information.
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