tjh.dev
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Documentation/laptops/00-INDEX
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Documentation/laptops/00-INDEX
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Documentation/laptops/toshiba_haps.txt
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Documentation/laptops/toshiba_haps.txt
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Kernel driver toshiba_haps
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Toshiba HDD Active Protection Sensor
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====================================
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Author: Azael Avalos <coproscefalo@gmail.com>
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0. Contents
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-----------
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1. Description
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2. Interface
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3. Accelerometer axes
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4. Supported devices
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5. Usage
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1. Description
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--------------
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This driver provides support for the accelerometer found in various Toshiba
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laptops, being called "Toshiba HDD Protection - Shock Sensor" officialy,
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and detects laptops automatically with this device.
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On Windows, Toshiba provided software monitors this device and provides
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automatic HDD protection (head unload) on sudden moves or harsh vibrations,
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however, this driver only provides a notification via a sysfs file to let
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userspace tools or daemons act accordingly, as well as providing a sysfs
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file to set the desired protection level or sensor sensibility.
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2. Interface
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------------
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This device comes with 3 methods:
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_STA - Checks existence of the device, returning Zero if the device does not
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exists or is not supported.
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PTLV - Sets the desired protection level.
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RSSS - Shuts down the HDD protection interface for a few seconds,
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then restores normal operation.
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Note:
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The presence of Solid State Drives (SSD) can make this driver to fail loading,
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given the fact that such drives have no movable parts, and thus, not requiring
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any "protection" as well as failing during the evaluation of the _STA method
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found under this device.
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3. Accelerometer axes
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---------------------
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This device does not report any axes, however, to query the sensor position
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a couple HCI (Hardware Configuration Interface) calls (0x6D and 0xA6) are
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provided to query such information, handled by the kernel module toshiba_acpi
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since kernel version 3.15.
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4. Supported devices
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--------------------
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This driver binds itself to the ACPI device TOS620A, and any Toshiba laptop
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with this device is supported, given the fact that they have the presence of
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conventional HDD and not only SSD, or a combination of both HDD and SSD.
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5. Usage
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--------
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The sysfs files under /sys/devices/LNXSYSTM:00/LNXSYBUS:00/TOS620A:00/ are:
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protection_level - The protection_level is readable and writeable, and
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provides a way to let userspace query the current protection
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level, as well as set the desired protection level, the
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available protection levels are:
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0 - Disabled | 1 - Low | 2 - Medium | 3 - High
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reset_protection - The reset_protection entry is writeable only, being "1"
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the only parameter it accepts, it is used to trigger
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a reset of the protection interface.