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 196 197