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Based on kernel version 3.13. Page generated on 2014-01-20 22:00 EST.

1	What:		/sys/firmware/acpi/bgrt/
2	Date:		January 2012
3	Contact:	Matthew Garrett <mjg@redhat.com>
4	Description:
5			The BGRT is an ACPI 5.0 feature that allows the OS
6			to obtain a copy of the firmware boot splash and
7			some associated metadata. This is intended to be used
8			by boot splash applications in order to interact with
9			the firmware boot splash in order to avoid jarring
10			transitions.
11	
12			image: The image bitmap. Currently a 32-bit BMP.
13			status: 1 if the image is valid, 0 if firmware invalidated it.
14			type: 0 indicates image is in BMP format.
15			version: The version of the BGRT. Currently 1.
16			xoffset: The number of pixels between the left of the screen
17				 and the left edge of the image.
18			yoffset: The number of pixels between the top of the screen
19				 and the top edge of the image.
20	
21	What:		/sys/firmware/acpi/hotplug/
22	Date:		February 2013
23	Contact:	Rafael J. Wysocki <rafael.j.wysocki@intel.com>
24	Description:
25			There are separate hotplug profiles for different classes of
26			devices supported by ACPI, such as containers, memory modules,
27			processors, PCI root bridges etc.  A hotplug profile for a given
28			class of devices is a collection of settings defining the way
29			that class of devices will be handled by the ACPI core hotplug
30			code.  Those profiles are represented in sysfs as subdirectories
31			of /sys/firmware/acpi/hotplug/.
32	
33			The following setting is available to user space for each
34			hotplug profile:
35	
36			enabled: If set, the ACPI core will handle notifications of
37				hotplug events associated with the given class of
38				devices and will allow those devices to be ejected with
39				the help of the _EJ0 control method.  Unsetting it
40				effectively disables hotplug for the correspoinding
41				class of devices.
42	
43			The value of the above attribute is an integer number: 1 (set)
44			or 0 (unset).  Attempts to write any other values to it will
45			cause -EINVAL to be returned.
46	
47	What:		/sys/firmware/acpi/hotplug/force_remove
48	Date:		May 2013
49	Contact:	Rafael J. Wysocki <rafael.j.wysocki@intel.com>
50	Description:
51			The number in this file (0 or 1) determines whether (1) or not
52			(0) the ACPI subsystem will allow devices to be hot-removed even
53			if they cannot be put offline gracefully (from the kernel's
54			viewpoint).  That number can be changed by writing a boolean
55			value to this file.
56	
57	What:		/sys/firmware/acpi/interrupts/
58	Date:		February 2008
59	Contact:	Len Brown <lenb@kernel.org>
60	Description:
61			All ACPI interrupts are handled via a single IRQ,
62			the System Control Interrupt (SCI), which appears
63			as "acpi" in /proc/interrupts.
64	
65			However, one of the main functions of ACPI is to make
66			the platform understand random hardware without
67			special driver support.  So while the SCI handles a few
68			well known (fixed feature) interrupts sources, such
69			as the power button, it can also handle a variable
70			number of a "General Purpose Events" (GPE).
71	
72			A GPE vectors to a specified handler in AML, which
73			can do a anything the BIOS writer wants from
74			OS context.  GPE 0x12, for example, would vector
75			to a level or edge handler called _L12 or _E12.
76			The handler may do its business and return.
77			Or the handler may send send a Notify event
78			to a Linux device driver registered on an ACPI device,
79			such as a battery, or a processor.
80	
81			To figure out where all the SCI's are coming from,
82			/sys/firmware/acpi/interrupts contains a file listing
83			every possible source, and the count of how many
84			times it has triggered.
85	
86			$ cd /sys/firmware/acpi/interrupts
87			$ grep . *
88			error:	     0
89			ff_gbl_lock:	   0   enable
90			ff_pmtimer:	  0  invalid
91			ff_pwr_btn:	  0   enable
92			ff_rt_clk:	 2  disable
93			ff_slp_btn:	  0  invalid
94			gpe00:	     0	invalid
95			gpe01:	     0	 enable
96			gpe02:	   108	 enable
97			gpe03:	     0	invalid
98			gpe04:	     0	invalid
99			gpe05:	     0	invalid
100			gpe06:	     0	 enable
101			gpe07:	     0	 enable
102			gpe08:	     0	invalid
103			gpe09:	     0	invalid
104			gpe0A:	     0	invalid
105			gpe0B:	     0	invalid
106			gpe0C:	     0	invalid
107			gpe0D:	     0	invalid
108			gpe0E:	     0	invalid
109			gpe0F:	     0	invalid
110			gpe10:	     0	invalid
111			gpe11:	     0	invalid
112			gpe12:	     0	invalid
113			gpe13:	     0	invalid
114			gpe14:	     0	invalid
115			gpe15:	     0	invalid
116			gpe16:	     0	invalid
117			gpe17:	  1084	 enable
118			gpe18:	     0	 enable
119			gpe19:	     0	invalid
120			gpe1A:	     0	invalid
121			gpe1B:	     0	invalid
122			gpe1C:	     0	invalid
123			gpe1D:	     0	invalid
124			gpe1E:	     0	invalid
125			gpe1F:	     0	invalid
126			gpe_all:    1192
127			sci:	1194
128			sci_not:     0	
129	
130			sci - The number of times the ACPI SCI
131			has been called and claimed an interrupt.
132	
133			sci_not - The number of times the ACPI SCI
134			has been called and NOT claimed an interrupt.
135	
136			gpe_all - count of SCI caused by GPEs.
137	
138			gpeXX - count for individual GPE source
139	
140			ff_gbl_lock - Global Lock
141	
142			ff_pmtimer - PM Timer
143	
144			ff_pwr_btn - Power Button
145	
146			ff_rt_clk - Real Time Clock
147	
148			ff_slp_btn - Sleep Button
149	
150			error - an interrupt that can't be accounted for above.
151	
152			invalid: it's either a GPE or a Fixed Event that
153				doesn't have an event handler.
154	
155			disable: the GPE/Fixed Event is valid but disabled.
156	
157			enable: the GPE/Fixed Event is valid and enabled.
158	
159			Root has permission to clear any of these counters.  Eg.
160			# echo 0 > gpe11
161	
162			All counters can be cleared by clearing the total "sci":
163			# echo 0 > sci
164	
165			None of these counters has an effect on the function
166			of the system, they are simply statistics.
167	
168			Besides this, user can also write specific strings to these files
169			to enable/disable/clear ACPI interrupts in user space, which can be
170			used to debug some ACPI interrupt storm issues.
171	
172			Note that only writting to VALID GPE/Fixed Event is allowed,
173			i.e. user can only change the status of runtime GPE and
174			Fixed Event with event handler installed.
175	
176			Let's take power button fixed event for example, please kill acpid
177			and other user space applications so that the machine won't shutdown
178			when pressing the power button.
179			# cat ff_pwr_btn
180			0	enabled
181			# press the power button for 3 times;
182			# cat ff_pwr_btn
183			3	enabled
184			# echo disable > ff_pwr_btn
185			# cat ff_pwr_btn
186			3	disabled
187			# press the power button for 3 times;
188			# cat ff_pwr_btn
189			3	disabled
190			# echo enable > ff_pwr_btn
191			# cat ff_pwr_btn
192			4	enabled
193			/*
194			 * this is because the status bit is set even if the enable bit is cleared,
195			 * and it triggers an ACPI fixed event when the enable bit is set again
196			 */
197			# press the power button for 3 times;
198			# cat ff_pwr_btn
199			7	enabled
200			# echo disable > ff_pwr_btn
201			# press the power button for 3 times;
202			# echo clear > ff_pwr_btn	/* clear the status bit */
203			# echo disable > ff_pwr_btn
204			# cat ff_pwr_btn
205			7	enabled
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