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 16 ======== =================================================== 17 version: The version of the BGRT. Currently 1. 18 xoffset: The number of pixels between the left of the screen 19 and the left edge of the image. 20 yoffset: The number of pixels between the top of the screen 21 and the top edge of the image. 22 ======== =================================================== 23 24What: /sys/firmware/acpi/hotplug/ 25Date: February 2013 26Contact: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 27Description: 28 There are separate hotplug profiles for different classes of 29 devices supported by ACPI, such as containers, memory modules, 30 processors, PCI root bridges etc. A hotplug profile for a given 31 class of devices is a collection of settings defining the way 32 that class of devices will be handled by the ACPI core hotplug 33 code. Those profiles are represented in sysfs as subdirectories 34 of /sys/firmware/acpi/hotplug/. 35 36 The following setting is available to user space for each 37 hotplug profile: 38 39 ======== ======================================================= 40 enabled: If set, the ACPI core will handle notifications of 41 hotplug events associated with the given class of 42 devices and will allow those devices to be ejected with 43 the help of the _EJ0 control method. Unsetting it 44 effectively disables hotplug for the correspoinding 45 class of devices. 46 ======== ======================================================= 47 48 The value of the above attribute is an integer number: 1 (set) 49 or 0 (unset). Attempts to write any other values to it will 50 cause -EINVAL to be returned. 51 52What: /sys/firmware/acpi/interrupts/ 53Date: February 2008 54Contact: Len Brown <lenb@kernel.org> 55Description: 56 All ACPI interrupts are handled via a single IRQ, 57 the System Control Interrupt (SCI), which appears 58 as "acpi" in /proc/interrupts. 59 60 However, one of the main functions of ACPI is to make 61 the platform understand random hardware without 62 special driver support. So while the SCI handles a few 63 well known (fixed feature) interrupts sources, such 64 as the power button, it can also handle a variable 65 number of a "General Purpose Events" (GPE). 66 67 A GPE vectors to a specified handler in AML, which 68 can do a anything the BIOS writer wants from 69 OS context. GPE 0x12, for example, would vector 70 to a level or edge handler called _L12 or _E12. 71 The handler may do its business and return. 72 Or the handler may send send a Notify event 73 to a Linux device driver registered on an ACPI device, 74 such as a battery, or a processor. 75 76 To figure out where all the SCI's are coming from, 77 /sys/firmware/acpi/interrupts contains a file listing 78 every possible source, and the count of how many 79 times it has triggered:: 80 81 $ cd /sys/firmware/acpi/interrupts 82 $ grep . * 83 error: 0 84 ff_gbl_lock: 0 enable 85 ff_pmtimer: 0 invalid 86 ff_pwr_btn: 0 enable 87 ff_rt_clk: 2 disable 88 ff_slp_btn: 0 invalid 89 gpe00: 0 invalid 90 gpe01: 0 enable 91 gpe02: 108 enable 92 gpe03: 0 invalid 93 gpe04: 0 invalid 94 gpe05: 0 invalid 95 gpe06: 0 enable 96 gpe07: 0 enable 97 gpe08: 0 invalid 98 gpe09: 0 invalid 99 gpe0A: 0 invalid 100 gpe0B: 0 invalid 101 gpe0C: 0 invalid 102 gpe0D: 0 invalid 103 gpe0E: 0 invalid 104 gpe0F: 0 invalid 105 gpe10: 0 invalid 106 gpe11: 0 invalid 107 gpe12: 0 invalid 108 gpe13: 0 invalid 109 gpe14: 0 invalid 110 gpe15: 0 invalid 111 gpe16: 0 invalid 112 gpe17: 1084 enable 113 gpe18: 0 enable 114 gpe19: 0 invalid 115 gpe1A: 0 invalid 116 gpe1B: 0 invalid 117 gpe1C: 0 invalid 118 gpe1D: 0 invalid 119 gpe1E: 0 invalid 120 gpe1F: 0 invalid 121 gpe_all: 1192 122 sci: 1194 123 sci_not: 0 124 125 =========== ================================================== 126 sci The number of times the ACPI SCI 127 has been called and claimed an interrupt. 128 129 sci_not The number of times the ACPI SCI 130 has been called and NOT claimed an interrupt. 131 132 gpe_all count of SCI caused by GPEs. 133 134 gpeXX count for individual GPE source 135 136 ff_gbl_lock Global Lock 137 138 ff_pmtimer PM Timer 139 140 ff_pwr_btn Power Button 141 142 ff_rt_clk Real Time Clock 143 144 ff_slp_btn Sleep Button 145 146 error an interrupt that can't be accounted for above. 147 148 invalid it's either a GPE or a Fixed Event that 149 doesn't have an event handler. 150 151 disable the GPE/Fixed Event is valid but disabled. 152 153 enable the GPE/Fixed Event is valid and enabled. 154 =========== ================================================== 155 156 Root has permission to clear any of these counters. Eg.:: 157 158 # echo 0 > gpe11 159 160 All counters can be cleared by clearing the total "sci":: 161 162 # echo 0 > sci 163 164 None of these counters has an effect on the function 165 of the system, they are simply statistics. 166 167 Besides this, user can also write specific strings to these files 168 to enable/disable/clear ACPI interrupts in user space, which can be 169 used to debug some ACPI interrupt storm issues. 170 171 Note that only writing to VALID GPE/Fixed Event is allowed, 172 i.e. user can only change the status of runtime GPE and 173 Fixed Event with event handler installed. 174 175 Let's take power button fixed event for example, please kill acpid 176 and other user space applications so that the machine won't shutdown 177 when pressing the power button:: 178 179 # 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 195 * bit is cleared, and it triggers an ACPI fixed event when 196 * the enable bit is set again 197 */ 198 # press the power button for 3 times; 199 # cat ff_pwr_btn 200 7 enabled 201 # echo disable > ff_pwr_btn 202 # press the power button for 3 times; 203 # echo clear > ff_pwr_btn /* clear the status bit */ 204 # echo disable > ff_pwr_btn 205 # cat ff_pwr_btn 206 7 enabled 207 208