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Based on kernel version 4.13.3. Page generated on 2017-09-23 13:54 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/interrupts/
48	Date:		February 2008
49	Contact:	Len Brown <lenb@kernel.org>
50	Description:
51			All ACPI interrupts are handled via a single IRQ,
52			the System Control Interrupt (SCI), which appears
53			as "acpi" in /proc/interrupts.
54	
55			However, one of the main functions of ACPI is to make
56			the platform understand random hardware without
57			special driver support.  So while the SCI handles a few
58			well known (fixed feature) interrupts sources, such
59			as the power button, it can also handle a variable
60			number of a "General Purpose Events" (GPE).
61	
62			A GPE vectors to a specified handler in AML, which
63			can do a anything the BIOS writer wants from
64			OS context.  GPE 0x12, for example, would vector
65			to a level or edge handler called _L12 or _E12.
66			The handler may do its business and return.
67			Or the handler may send send a Notify event
68			to a Linux device driver registered on an ACPI device,
69			such as a battery, or a processor.
70	
71			To figure out where all the SCI's are coming from,
72			/sys/firmware/acpi/interrupts contains a file listing
73			every possible source, and the count of how many
74			times it has triggered.
75	
76			$ cd /sys/firmware/acpi/interrupts
77			$ grep . *
78			error:	     0
79			ff_gbl_lock:	   0   enable
80			ff_pmtimer:	  0  invalid
81			ff_pwr_btn:	  0   enable
82			ff_rt_clk:	 2  disable
83			ff_slp_btn:	  0  invalid
84			gpe00:	     0	invalid
85			gpe01:	     0	 enable
86			gpe02:	   108	 enable
87			gpe03:	     0	invalid
88			gpe04:	     0	invalid
89			gpe05:	     0	invalid
90			gpe06:	     0	 enable
91			gpe07:	     0	 enable
92			gpe08:	     0	invalid
93			gpe09:	     0	invalid
94			gpe0A:	     0	invalid
95			gpe0B:	     0	invalid
96			gpe0C:	     0	invalid
97			gpe0D:	     0	invalid
98			gpe0E:	     0	invalid
99			gpe0F:	     0	invalid
100			gpe10:	     0	invalid
101			gpe11:	     0	invalid
102			gpe12:	     0	invalid
103			gpe13:	     0	invalid
104			gpe14:	     0	invalid
105			gpe15:	     0	invalid
106			gpe16:	     0	invalid
107			gpe17:	  1084	 enable
108			gpe18:	     0	 enable
109			gpe19:	     0	invalid
110			gpe1A:	     0	invalid
111			gpe1B:	     0	invalid
112			gpe1C:	     0	invalid
113			gpe1D:	     0	invalid
114			gpe1E:	     0	invalid
115			gpe1F:	     0	invalid
116			gpe_all:    1192
117			sci:	1194
118			sci_not:     0	
119	
120			sci - The number of times the ACPI SCI
121			has been called and claimed an interrupt.
122	
123			sci_not - The number of times the ACPI SCI
124			has been called and NOT claimed an interrupt.
125	
126			gpe_all - count of SCI caused by GPEs.
127	
128			gpeXX - count for individual GPE source
129	
130			ff_gbl_lock - Global Lock
131	
132			ff_pmtimer - PM Timer
133	
134			ff_pwr_btn - Power Button
135	
136			ff_rt_clk - Real Time Clock
137	
138			ff_slp_btn - Sleep Button
139	
140			error - an interrupt that can't be accounted for above.
141	
142			invalid: it's either a GPE or a Fixed Event that
143				doesn't have an event handler.
144	
145			disable: the GPE/Fixed Event is valid but disabled.
146	
147			enable: the GPE/Fixed Event is valid and enabled.
148	
149			Root has permission to clear any of these counters.  Eg.
150			# echo 0 > gpe11
151	
152			All counters can be cleared by clearing the total "sci":
153			# echo 0 > sci
154	
155			None of these counters has an effect on the function
156			of the system, they are simply statistics.
157	
158			Besides this, user can also write specific strings to these files
159			to enable/disable/clear ACPI interrupts in user space, which can be
160			used to debug some ACPI interrupt storm issues.
161	
162			Note that only writing to VALID GPE/Fixed Event is allowed,
163			i.e. user can only change the status of runtime GPE and
164			Fixed Event with event handler installed.
165	
166			Let's take power button fixed event for example, please kill acpid
167			and other user space applications so that the machine won't shutdown
168			when pressing the power button.
169			# cat ff_pwr_btn
170			0	enabled
171			# press the power button for 3 times;
172			# cat ff_pwr_btn
173			3	enabled
174			# echo disable > ff_pwr_btn
175			# cat ff_pwr_btn
176			3	disabled
177			# press the power button for 3 times;
178			# cat ff_pwr_btn
179			3	disabled
180			# echo enable > ff_pwr_btn
181			# cat ff_pwr_btn
182			4	enabled
183			/*
184			 * this is because the status bit is set even if the enable bit is cleared,
185			 * and it triggers an ACPI fixed event when the enable bit is set again
186			 */
187			# press the power button for 3 times;
188			# cat ff_pwr_btn
189			7	enabled
190			# echo disable > ff_pwr_btn
191			# press the power button for 3 times;
192			# echo clear > ff_pwr_btn	/* clear the status bit */
193			# echo disable > ff_pwr_btn
194			# cat ff_pwr_btn
195			7	enabled
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