About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Documentation / laptops / toshiba_haps.txt




Custom Search

Based on kernel version 4.16.1. Page generated on 2018-04-09 11:53 EST.

1	Kernel driver toshiba_haps
2	Toshiba HDD Active Protection Sensor
3	====================================
4	
5	Author: Azael Avalos <coproscefalo@gmail.com>
6	
7	
8	0. Contents
9	-----------
10	
11	1. Description
12	2. Interface
13	3. Accelerometer axes
14	4. Supported devices
15	5. Usage
16	
17	
18	1. Description
19	--------------
20	
21	This driver provides support for the accelerometer found in various Toshiba
22	laptops, being called "Toshiba HDD Protection - Shock Sensor" officially,
23	and detects laptops automatically with this device.
24	On Windows, Toshiba provided software monitors this device and provides
25	automatic HDD protection (head unload) on sudden moves or harsh vibrations,
26	however, this driver only provides a notification via a sysfs file to let
27	userspace tools or daemons act accordingly, as well as providing a sysfs
28	file to set the desired protection level or sensor sensibility.
29	
30	
31	2. Interface
32	------------
33	
34	This device comes with 3 methods:
35	_STA -  Checks existence of the device, returning Zero if the device does not
36		exists or is not supported.
37	PTLV -  Sets the desired protection level.
38	RSSS -  Shuts down the HDD protection interface for a few seconds,
39		then restores normal operation.
40	
41	Note:
42	The presence of Solid State Drives (SSD) can make this driver to fail loading,
43	given the fact that such drives have no movable parts, and thus, not requiring
44	any "protection" as well as failing during the evaluation of the _STA method
45	found under this device.
46	
47	
48	3. Accelerometer axes
49	---------------------
50	
51	This device does not report any axes, however, to query the sensor position
52	a couple HCI (Hardware Configuration Interface) calls (0x6D and 0xA6) are
53	provided to query such information, handled by the kernel module toshiba_acpi
54	since kernel version 3.15.
55	
56	
57	4. Supported devices
58	--------------------
59	
60	This driver binds itself to the ACPI device TOS620A, and any Toshiba laptop
61	with this device is supported, given the fact that they have the presence of
62	conventional HDD and not only SSD, or a combination of both HDD and SSD.
63	
64	
65	5. Usage
66	--------
67	
68	The sysfs files under /sys/devices/LNXSYSTM:00/LNXSYBUS:00/TOS620A:00/ are:
69	protection_level - The protection_level is readable and writeable, and
70			   provides a way to let userspace query the current protection
71			   level, as well as set the desired protection level, the
72			   available protection levels are:
73			   0 - Disabled | 1 - Low | 2 - Medium | 3 - High
74	reset_protection - The reset_protection entry is writeable only, being "1"
75			   the only parameter it accepts, it is used to trigger
76			   a reset of the protection interface.
Hide Line Numbers
About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Information is copyright its respective author. All material is available from the Linux Kernel Source distributed under a GPL License. This page is provided as a free service by mjmwired.net.