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1What: /sys/firmware/acpi/interrupts/
2Date: February 2008
3Contact: Len Brown <lenb@kernel.org>
4Description:
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
150
1What: /sys/firmware/acpi/bgrt/
2Date: January 2012
3Contact: Matthew Garrett <mjg@redhat.com>
4Description:
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
21What: /sys/firmware/acpi/hotplug/
22Date: February 2013
23Contact: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
24Description:
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
47What: /sys/firmware/acpi/interrupts/
48Date: February 2008
49Contact: Len Brown <lenb@kernel.org>
50Description:
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
196