| What: /sys/firmware/acpi/interrupts/ |
| Date: February 2008 |
| Contact: Len Brown <lenb@kernel.org> |
| Description: |
| All ACPI interrupts are handled via a single IRQ, |
| the System Control Interrupt (SCI), which appears |
| as "acpi" in /proc/interrupts. |
| |
| However, one of the main functions of ACPI is to make |
| the platform understand random hardware without |
| special driver support. So while the SCI handles a few |
| well known (fixed feature) interrupts sources, such |
| as the power button, it can also handle a variable |
| number of a "General Purpose Events" (GPE). |
| |
| A GPE vectors to a specified handler in AML, which |
| can do a anything the BIOS writer wants from |
| OS context. GPE 0x12, for example, would vector |
| to a level or edge handler called _L12 or _E12. |
| The handler may do its business and return. |
| Or the handler may send send a Notify event |
| to a Linux device driver registered on an ACPI device, |
| such as a battery, or a processor. |
| |
| To figure out where all the SCI's are coming from, |
| /sys/firmware/acpi/interrupts contains a file listing |
| every possible source, and the count of how many |
| times it has triggered. |
| |
| $ cd /sys/firmware/acpi/interrupts |
| $ grep . * |
| error:0 |
| ff_gbl_lock:0 |
| ff_pmtimer:0 |
| ff_pwr_btn:0 |
| ff_rt_clk:0 |
| ff_slp_btn:0 |
| gpe00:0 |
| gpe01:0 |
| gpe02:0 |
| gpe03:0 |
| gpe04:0 |
| gpe05:0 |
| gpe06:0 |
| gpe07:0 |
| gpe08:0 |
| gpe09:174 |
| gpe0A:0 |
| gpe0B:0 |
| gpe0C:0 |
| gpe0D:0 |
| gpe0E:0 |
| gpe0F:0 |
| gpe10:0 |
| gpe11:60 |
| gpe12:0 |
| gpe13:0 |
| gpe14:0 |
| gpe15:0 |
| gpe16:0 |
| gpe17:0 |
| gpe18:0 |
| gpe19:7 |
| gpe1A:0 |
| gpe1B:0 |
| gpe1C:0 |
| gpe1D:0 |
| gpe1E:0 |
| gpe1F:0 |
| gpe_all:241 |
| sci:241 |
| |
| sci - The total number of times the ACPI SCI |
| has claimed an interrupt. |
| |
| gpe_all - count of SCI caused by GPEs. |
| |
| gpeXX - count for individual GPE source |
| |
| ff_gbl_lock - Global Lock |
| |
| ff_pmtimer - PM Timer |
| |
| ff_pwr_btn - Power Button |
| |
| ff_rt_clk - Real Time Clock |
| |
| ff_slp_btn - Sleep Button |
| |
| error - an interrupt that can't be accounted for above. |
| |
| Root has permission to clear any of these counters. Eg. |
| # echo 0 > gpe11 |
| |
| All counters can be cleared by clearing the total "sci": |
| # echo 0 > sci |
| |
| None of these counters has an effect on the function |
| of the system, they are simply statistics. |
