dcfbd31ef4
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>
2.0 KiB
What: /sys/bus/platform/devices/INTC1092:00/intc_reg Date: August 2021 KernelVersion: 5.15 Contact: Shravan S s.shravan@intel.com, An Sudhakar sudhakar.an@intel.com Description: Specific Absorption Rate (SAR) regulatory mode is typically derived based on information like mcc (Mobile Country Code) and mnc (Mobile Network Code) that is available for the currently attached LTE network. A userspace application is required to set the current SAR regulatory mode on the Dynamic SAR driver using this sysfs node. Such an application can also read back using this sysfs node, the currently configured regulatory mode value from the Dynamic SAR driver.
Acceptable regulatory modes are:
== ====
0 FCC
1 CE
2 ISED
== ====
- The regulatory mode value has one of the above values.
- The default regulatory mode used in the driver is 0.
What: /sys/bus/platform/devices/INTC1092:00/intc_data Date: August 2021 KernelVersion: 5.15 Contact: Shravan S s.shravan@intel.com, An Sudhakar sudhakar.an@intel.com Description: This sysfs entry is used to retrieve Dynamic SAR information emitted/maintained by a BIOS that supports Dynamic SAR.
The retrieved information is in the order given below:
- device_mode
- bandtable_index
- antennatable_index
- sartable_index
The above information is sent as integer values separated
by a single space. This information can then be pushed to a
WWAN modem that uses this to control the transmit signal
level using the Band/Antenna/SAR table index information.
These parameters are derived/decided by aggregating
device-mode like laptop/tablet/clamshell etc. and the
proximity-sensor data available to the embedded controller on
given host. The regulatory mode configured on Dynamic SAR
driver also influences these values.
The userspace applications can poll for changes to this file
using POLLPRI event on file-descriptor (fd) obtained by opening
this sysfs entry. Application can then read this information from
the sysfs node and consume the given information.