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Based on kernel version 3.3. Page generated on 2012-03-23 21:23 EST.

1	What:		/sys/firmware/acpi/interrupts/
2	Date:		February 2008
3	Contact:	Len Brown <lenb@kernel.org>
4	Description:
5			All ACPI interrupts are handled via a single IRQ,
6			the System Control Interrupt (SCI), which appears
7			as "acpi" in /proc/interrupts.
8	
9			However, one of the main functions of ACPI is to make
10			the platform understand random hardware without
11			special driver support.  So while the SCI handles a few
12			well known (fixed feature) interrupts sources, such
13			as the power button, it can also handle a variable
14			number of a "General Purpose Events" (GPE).
15	
16			A GPE vectors to a specified handler in AML, which
17			can do a anything the BIOS writer wants from
18			OS context.  GPE 0x12, for example, would vector
19			to a level or edge handler called _L12 or _E12.
20			The handler may do its business and return.
21			Or the handler may send send a Notify event
22			to a Linux device driver registered on an ACPI device,
23			such as a battery, or a processor.
24	
25			To figure out where all the SCI's are coming from,
26			/sys/firmware/acpi/interrupts contains a file listing
27			every possible source, and the count of how many
28			times it has triggered.
29	
30			$ cd /sys/firmware/acpi/interrupts
31			$ grep . *
32			error:	     0
33			ff_gbl_lock:	   0   enable
34			ff_pmtimer:	  0  invalid
35			ff_pwr_btn:	  0   enable
36			ff_rt_clk:	 2  disable
37			ff_slp_btn:	  0  invalid
38			gpe00:	     0	invalid
39			gpe01:	     0	 enable
40			gpe02:	   108	 enable
41			gpe03:	     0	invalid
42			gpe04:	     0	invalid
43			gpe05:	     0	invalid
44			gpe06:	     0	 enable
45			gpe07:	     0	 enable
46			gpe08:	     0	invalid
47			gpe09:	     0	invalid
48			gpe0A:	     0	invalid
49			gpe0B:	     0	invalid
50			gpe0C:	     0	invalid
51			gpe0D:	     0	invalid
52			gpe0E:	     0	invalid
53			gpe0F:	     0	invalid
54			gpe10:	     0	invalid
55			gpe11:	     0	invalid
56			gpe12:	     0	invalid
57			gpe13:	     0	invalid
58			gpe14:	     0	invalid
59			gpe15:	     0	invalid
60			gpe16:	     0	invalid
61			gpe17:	  1084	 enable
62			gpe18:	     0	 enable
63			gpe19:	     0	invalid
64			gpe1A:	     0	invalid
65			gpe1B:	     0	invalid
66			gpe1C:	     0	invalid
67			gpe1D:	     0	invalid
68			gpe1E:	     0	invalid
69			gpe1F:	     0	invalid
70			gpe_all:    1192
71			sci:	1194
72			sci_not:     0	
73	
74			sci - The number of times the ACPI SCI
75			has been called and claimed an interrupt.
76	
77			sci_not - The number of times the ACPI SCI
78			has been called and NOT claimed an interrupt.
79	
80			gpe_all - count of SCI caused by GPEs.
81	
82			gpeXX - count for individual GPE source
83	
84			ff_gbl_lock - Global Lock
85	
86			ff_pmtimer - PM Timer
87	
88			ff_pwr_btn - Power Button
89	
90			ff_rt_clk - Real Time Clock
91	
92			ff_slp_btn - Sleep Button
93	
94			error - an interrupt that can't be accounted for above.
95	
96			invalid: it's either a GPE or a Fixed Event that
97				doesn't have an event handler.
98	
99			disable: the GPE/Fixed Event is valid but disabled.
100	
101			enable: the GPE/Fixed Event is valid and enabled.
102	
103			Root has permission to clear any of these counters.  Eg.
104			# echo 0 > gpe11
105	
106			All counters can be cleared by clearing the total "sci":
107			# echo 0 > sci
108	
109			None of these counters has an effect on the function
110			of the system, they are simply statistics.
111	
112			Besides this, user can also write specific strings to these files
113			to enable/disable/clear ACPI interrupts in user space, which can be
114			used to debug some ACPI interrupt storm issues.
115	
116			Note that only writting to VALID GPE/Fixed Event is allowed,
117			i.e. user can only change the status of runtime GPE and
118			Fixed Event with event handler installed.
119	
120			Let's take power button fixed event for example, please kill acpid
121			and other user space applications so that the machine won't shutdown
122			when pressing the power button.
123			# cat ff_pwr_btn
124			0	enabled
125			# press the power button for 3 times;
126			# cat ff_pwr_btn
127			3	enabled
128			# echo disable > ff_pwr_btn
129			# cat ff_pwr_btn
130			3	disabled
131			# press the power button for 3 times;
132			# cat ff_pwr_btn
133			3	disabled
134			# echo enable > ff_pwr_btn
135			# cat ff_pwr_btn
136			4	enabled
137			/*
138			 * this is because the status bit is set even if the enable bit is cleared,
139			 * and it triggers an ACPI fixed event when the enable bit is set again
140			 */
141			# press the power button for 3 times;
142			# cat ff_pwr_btn
143			7	enabled
144			# echo disable > ff_pwr_btn
145			# press the power button for 3 times;
146			# echo clear > ff_pwr_btn	/* clear the status bit */
147			# echo disable > ff_pwr_btn
148			# cat ff_pwr_btn
149			7	enabled
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