1d1ff4b1cSMatthew GarrettWhat:		/sys/firmware/acpi/bgrt/
2d1ff4b1cSMatthew GarrettDate:		January 2012
3d1ff4b1cSMatthew GarrettContact:	Matthew Garrett <mjg@redhat.com>
4d1ff4b1cSMatthew GarrettDescription:
5d1ff4b1cSMatthew Garrett		The BGRT is an ACPI 5.0 feature that allows the OS
6d1ff4b1cSMatthew Garrett		to obtain a copy of the firmware boot splash and
7d1ff4b1cSMatthew Garrett		some associated metadata. This is intended to be used
8d1ff4b1cSMatthew Garrett		by boot splash applications in order to interact with
9d1ff4b1cSMatthew Garrett		the firmware boot splash in order to avoid jarring
10d1ff4b1cSMatthew Garrett		transitions.
11d1ff4b1cSMatthew Garrett
12d1ff4b1cSMatthew Garrett		image: The image bitmap. Currently a 32-bit BMP.
13d1ff4b1cSMatthew Garrett		status: 1 if the image is valid, 0 if firmware invalidated it.
14d1ff4b1cSMatthew Garrett		type: 0 indicates image is in BMP format.
15d1ff4b1cSMatthew Garrett		version: The version of the BGRT. Currently 1.
16d1ff4b1cSMatthew Garrett		xoffset: The number of pixels between the left of the screen
17d1ff4b1cSMatthew Garrett			 and the left edge of the image.
18d1ff4b1cSMatthew Garrett		yoffset: The number of pixels between the top of the screen
19d1ff4b1cSMatthew Garrett			 and the top edge of the image.
20d1ff4b1cSMatthew Garrett
213f8055c3SRafael J. WysockiWhat:		/sys/firmware/acpi/hotplug/
223f8055c3SRafael J. WysockiDate:		February 2013
233f8055c3SRafael J. WysockiContact:	Rafael J. Wysocki <rafael.j.wysocki@intel.com>
243f8055c3SRafael J. WysockiDescription:
253f8055c3SRafael J. Wysocki		There are separate hotplug profiles for different classes of
263f8055c3SRafael J. Wysocki		devices supported by ACPI, such as containers, memory modules,
273f8055c3SRafael J. Wysocki		processors, PCI root bridges etc.  A hotplug profile for a given
283f8055c3SRafael J. Wysocki		class of devices is a collection of settings defining the way
293f8055c3SRafael J. Wysocki		that class of devices will be handled by the ACPI core hotplug
303f8055c3SRafael J. Wysocki		code.  Those profiles are represented in sysfs as subdirectories
313f8055c3SRafael J. Wysocki		of /sys/firmware/acpi/hotplug/.
323f8055c3SRafael J. Wysocki
333f8055c3SRafael J. Wysocki		The following setting is available to user space for each
343f8055c3SRafael J. Wysocki		hotplug profile:
353f8055c3SRafael J. Wysocki
363f8055c3SRafael J. Wysocki		enabled: If set, the ACPI core will handle notifications of
373f8055c3SRafael J. Wysocki			hotplug events associated with the given class of
383f8055c3SRafael J. Wysocki			devices and will allow those devices to be ejected with
393f8055c3SRafael J. Wysocki			the help of the _EJ0 control method.  Unsetting it
403f8055c3SRafael J. Wysocki			effectively disables hotplug for the correspoinding
413f8055c3SRafael J. Wysocki			class of devices.
423f8055c3SRafael J. Wysocki
433f8055c3SRafael J. Wysocki		The value of the above attribute is an integer number: 1 (set)
443f8055c3SRafael J. Wysocki		or 0 (unset).  Attempts to write any other values to it will
453f8055c3SRafael J. Wysocki		cause -EINVAL to be returned.
463f8055c3SRafael J. Wysocki
47683058e3SRafael J. WysockiWhat:		/sys/firmware/acpi/hotplug/force_remove
48683058e3SRafael J. WysockiDate:		May 2013
49683058e3SRafael J. WysockiContact:	Rafael J. Wysocki <rafael.j.wysocki@intel.com>
50683058e3SRafael J. WysockiDescription:
51683058e3SRafael J. Wysocki		The number in this file (0 or 1) determines whether (1) or not
52683058e3SRafael J. Wysocki		(0) the ACPI subsystem will allow devices to be hot-removed even
53683058e3SRafael J. Wysocki		if they cannot be put offline gracefully (from the kernel's
54683058e3SRafael J. Wysocki		viewpoint).  That number can be changed by writing a boolean
55683058e3SRafael J. Wysocki		value to this file.
56683058e3SRafael J. Wysocki
575229e87dSLen BrownWhat:		/sys/firmware/acpi/interrupts/
585229e87dSLen BrownDate:		February 2008
595229e87dSLen BrownContact:	Len Brown <lenb@kernel.org>
605229e87dSLen BrownDescription:
615229e87dSLen Brown		All ACPI interrupts are handled via a single IRQ,
625229e87dSLen Brown		the System Control Interrupt (SCI), which appears
635229e87dSLen Brown		as "acpi" in /proc/interrupts.
645229e87dSLen Brown
655229e87dSLen Brown		However, one of the main functions of ACPI is to make
665229e87dSLen Brown		the platform understand random hardware without
675229e87dSLen Brown		special driver support.  So while the SCI handles a few
685229e87dSLen Brown		well known (fixed feature) interrupts sources, such
695229e87dSLen Brown		as the power button, it can also handle a variable
705229e87dSLen Brown		number of a "General Purpose Events" (GPE).
715229e87dSLen Brown
725229e87dSLen Brown		A GPE vectors to a specified handler in AML, which
735229e87dSLen Brown		can do a anything the BIOS writer wants from
745229e87dSLen Brown		OS context.  GPE 0x12, for example, would vector
755229e87dSLen Brown		to a level or edge handler called _L12 or _E12.
765229e87dSLen Brown		The handler may do its business and return.
775229e87dSLen Brown		Or the handler may send send a Notify event
785229e87dSLen Brown		to a Linux device driver registered on an ACPI device,
795229e87dSLen Brown		such as a battery, or a processor.
805229e87dSLen Brown
815229e87dSLen Brown		To figure out where all the SCI's are coming from,
825229e87dSLen Brown		/sys/firmware/acpi/interrupts contains a file listing
835229e87dSLen Brown		every possible source, and the count of how many
845229e87dSLen Brown		times it has triggered.
855229e87dSLen Brown
865229e87dSLen Brown		$ cd /sys/firmware/acpi/interrupts
875229e87dSLen Brown		$ grep . *
885229e87dSLen Brown		error:	     0
8971b58cbbSZhang Rui		ff_gbl_lock:	   0   enable
9071b58cbbSZhang Rui		ff_pmtimer:	  0  invalid
9171b58cbbSZhang Rui		ff_pwr_btn:	  0   enable
9271b58cbbSZhang Rui		ff_rt_clk:	 2  disable
9371b58cbbSZhang Rui		ff_slp_btn:	  0  invalid
9471b58cbbSZhang Rui		gpe00:	     0	invalid
9571b58cbbSZhang Rui		gpe01:	     0	 enable
9671b58cbbSZhang Rui		gpe02:	   108	 enable
9771b58cbbSZhang Rui		gpe03:	     0	invalid
9871b58cbbSZhang Rui		gpe04:	     0	invalid
9971b58cbbSZhang Rui		gpe05:	     0	invalid
10071b58cbbSZhang Rui		gpe06:	     0	 enable
10171b58cbbSZhang Rui		gpe07:	     0	 enable
10271b58cbbSZhang Rui		gpe08:	     0	invalid
10371b58cbbSZhang Rui		gpe09:	     0	invalid
10471b58cbbSZhang Rui		gpe0A:	     0	invalid
10571b58cbbSZhang Rui		gpe0B:	     0	invalid
10671b58cbbSZhang Rui		gpe0C:	     0	invalid
10771b58cbbSZhang Rui		gpe0D:	     0	invalid
10871b58cbbSZhang Rui		gpe0E:	     0	invalid
10971b58cbbSZhang Rui		gpe0F:	     0	invalid
11071b58cbbSZhang Rui		gpe10:	     0	invalid
11171b58cbbSZhang Rui		gpe11:	     0	invalid
11271b58cbbSZhang Rui		gpe12:	     0	invalid
11371b58cbbSZhang Rui		gpe13:	     0	invalid
11471b58cbbSZhang Rui		gpe14:	     0	invalid
11571b58cbbSZhang Rui		gpe15:	     0	invalid
11671b58cbbSZhang Rui		gpe16:	     0	invalid
11771b58cbbSZhang Rui		gpe17:	  1084	 enable
11871b58cbbSZhang Rui		gpe18:	     0	 enable
11971b58cbbSZhang Rui		gpe19:	     0	invalid
12071b58cbbSZhang Rui		gpe1A:	     0	invalid
12171b58cbbSZhang Rui		gpe1B:	     0	invalid
12271b58cbbSZhang Rui		gpe1C:	     0	invalid
12371b58cbbSZhang Rui		gpe1D:	     0	invalid
12471b58cbbSZhang Rui		gpe1E:	     0	invalid
12571b58cbbSZhang Rui		gpe1F:	     0	invalid
12671b58cbbSZhang Rui		gpe_all:    1192
12771b58cbbSZhang Rui		sci:	1194
12888bea188SLen Brown		sci_not:     0
1295229e87dSLen Brown
13088bea188SLen Brown		sci - The number of times the ACPI SCI
13188bea188SLen Brown		has been called and claimed an interrupt.
13288bea188SLen Brown
13388bea188SLen Brown		sci_not - The number of times the ACPI SCI
13488bea188SLen Brown		has been called and NOT claimed an interrupt.
1355229e87dSLen Brown
1365229e87dSLen Brown		gpe_all - count of SCI caused by GPEs.
1375229e87dSLen Brown
1385229e87dSLen Brown		gpeXX - count for individual GPE source
1395229e87dSLen Brown
1405229e87dSLen Brown		ff_gbl_lock - Global Lock
1415229e87dSLen Brown
1425229e87dSLen Brown		ff_pmtimer - PM Timer
1435229e87dSLen Brown
1445229e87dSLen Brown		ff_pwr_btn - Power Button
1455229e87dSLen Brown
1465229e87dSLen Brown		ff_rt_clk - Real Time Clock
1475229e87dSLen Brown
1485229e87dSLen Brown		ff_slp_btn - Sleep Button
1495229e87dSLen Brown
1505229e87dSLen Brown		error - an interrupt that can't be accounted for above.
1515229e87dSLen Brown
152ed206facSZhang Rui		invalid: it's either a GPE or a Fixed Event that
15371b58cbbSZhang Rui			doesn't have an event handler.
15471b58cbbSZhang Rui
15571b58cbbSZhang Rui		disable: the GPE/Fixed Event is valid but disabled.
15671b58cbbSZhang Rui
15771b58cbbSZhang Rui		enable: the GPE/Fixed Event is valid and enabled.
15871b58cbbSZhang Rui
1595229e87dSLen Brown		Root has permission to clear any of these counters.  Eg.
1605229e87dSLen Brown		# echo 0 > gpe11
1615229e87dSLen Brown
1625229e87dSLen Brown		All counters can be cleared by clearing the total "sci":
1635229e87dSLen Brown		# echo 0 > sci
1645229e87dSLen Brown
1655229e87dSLen Brown		None of these counters has an effect on the function
1665229e87dSLen Brown		of the system, they are simply statistics.
16771b58cbbSZhang Rui
16871b58cbbSZhang Rui		Besides this, user can also write specific strings to these files
16971b58cbbSZhang Rui		to enable/disable/clear ACPI interrupts in user space, which can be
17071b58cbbSZhang Rui		used to debug some ACPI interrupt storm issues.
17171b58cbbSZhang Rui
17208559657SKees Cook		Note that only writing to VALID GPE/Fixed Event is allowed,
17371b58cbbSZhang Rui		i.e. user can only change the status of runtime GPE and
17471b58cbbSZhang Rui		Fixed Event with event handler installed.
17571b58cbbSZhang Rui
17671b58cbbSZhang Rui		Let's take power button fixed event for example, please kill acpid
17771b58cbbSZhang Rui		and other user space applications so that the machine won't shutdown
17871b58cbbSZhang Rui		when pressing the power button.
17971b58cbbSZhang Rui		# cat ff_pwr_btn
180ed206facSZhang Rui		0	enabled
18171b58cbbSZhang Rui		# press the power button for 3 times;
18271b58cbbSZhang Rui		# cat ff_pwr_btn
183ed206facSZhang Rui		3	enabled
18471b58cbbSZhang Rui		# echo disable > ff_pwr_btn
18571b58cbbSZhang Rui		# cat ff_pwr_btn
186ed206facSZhang Rui		3	disabled
18771b58cbbSZhang Rui		# press the power button for 3 times;
18871b58cbbSZhang Rui		# cat ff_pwr_btn
189ed206facSZhang Rui		3	disabled
19071b58cbbSZhang Rui		# echo enable > ff_pwr_btn
19171b58cbbSZhang Rui		# cat ff_pwr_btn
192ed206facSZhang Rui		4	enabled
19371b58cbbSZhang Rui		/*
19471b58cbbSZhang Rui		 * this is because the status bit is set even if the enable bit is cleared,
19571b58cbbSZhang Rui		 * and it triggers an ACPI fixed event when the enable bit is set again
19671b58cbbSZhang Rui		 */
19771b58cbbSZhang Rui		# press the power button for 3 times;
19871b58cbbSZhang Rui		# cat ff_pwr_btn
199ed206facSZhang Rui		7	enabled
20071b58cbbSZhang Rui		# echo disable > ff_pwr_btn
20171b58cbbSZhang Rui		# press the power button for 3 times;
20271b58cbbSZhang Rui		# echo clear > ff_pwr_btn	/* clear the status bit */
20371b58cbbSZhang Rui		# echo disable > ff_pwr_btn
20471b58cbbSZhang Rui		# cat ff_pwr_btn
205ed206facSZhang Rui		7	enabled
20671b58cbbSZhang Rui
207