Sometimes, the users may require a quirk to be provided from ACPI subsystem core to prevent a GPE from flooding. Normally, if a GPE cannot be dispatched, ACPICA core automatically prevents the GPE from firing. But there are cases the GPE is dispatched by _Lxx/_Exx provided via AML table, and OSPM is lacking of the knowledge to get _Lxx/_Exx correctly executed to handle the GPE, thus the GPE flooding may still occur. This patch provides a quirk mechanism to stop this kind of GPE flooding. Link: https://bugzilla.kernel.org/show_bug.cgi?id=53071 Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/887793 Signed-off-by: Lv Zheng <lv.zheng@xxxxxxxxx> --- Documentation/kernel-parameters.txt | 10 +++++++ drivers/acpi/internal.h | 1 + drivers/acpi/scan.c | 1 + drivers/acpi/sysfs.c | 56 +++++++++++++++++++++++++++++++++++ 4 files changed, 68 insertions(+) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 769db83..06db98d 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -274,6 +274,16 @@ bytes respectively. Such letter suffixes can also be entirely omitted. use by PCI Format: <irq>,<irq>... + acpi_mask_gpe= [HW,ACPI] + Due to the existence of _Lxx/_Exx, some GPEs triggered + by unsupported hardware/firmware features can result in + GPE floodings that cannot be automatically disabled by + the GPE dispatcher. + This facility can be used to prevent such uncontrolled + GPE floodings. + Format: <int> + Support masking of GPEs numbered from 0x00 to 0x63. + acpi_no_auto_serialize [HW,ACPI] Disable auto-serialization of AML methods AML control methods that contain the opcodes to create diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h index 940218f..63052a8 100644 --- a/drivers/acpi/internal.h +++ b/drivers/acpi/internal.h @@ -37,6 +37,7 @@ void acpi_amba_init(void); static inline void acpi_amba_init(void) {} #endif int acpi_sysfs_init(void); +void acpi_gpe_apply_masked_gpes(void); void acpi_container_init(void); void acpi_memory_hotplug_init(void); #ifdef CONFIG_ACPI_HOTPLUG_IOAPIC diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 405056b..4e89702 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -1969,6 +1969,7 @@ int __init acpi_scan_init(void) } } + acpi_gpe_apply_masked_gpes(); acpi_update_all_gpes(); acpi_scan_initialized = true; diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c index 703c993..fecbf42 100644 --- a/drivers/acpi/sysfs.c +++ b/drivers/acpi/sysfs.c @@ -702,6 +702,62 @@ end: return result ? result : size; } +/* + * A Quirk Mechanism for GPE Flooding Prevention: + * + * Quirks may be needed to prevent GPE flooding on a specific GPE. The + * flooding typically cannot be detected and automatically prevented by + * ACPI_GPE_DISPATCH_NONE check because there is a _Lxx/_Exx prepared in + * the AML tables. This normally indicates a feature gap in Linux, thus + * instead of providing endless quirk tables, we provide a boot parameter + * for those who want this quirk. For example, if the users want to prevent + * the GPE flooding for GPE 00, they need to specify the following boot + * parameter: + * acpi_mask_gpe=0x00 + * The masking status can be modified by the following runtime controlling + * interface: + * echo unmask > /sys/firmware/acpi/interrupts/gpe00 + */ + +/* + * Currently, the GPE flooding prevention only supports to mask the GPEs + * numbered from 00 to 63. + */ +#define ACPI_MASKABLE_GPE_MAX 64 + +static u64 acpi_masked_gpes; + +static int __init acpi_gpe_set_masked_gpes(char *val) +{ + u8 gpe; + + if (kstrtou8(val, 0, &gpe) || gpe > ACPI_MASKABLE_GPE_MAX) + return -EINVAL; + acpi_masked_gpes |= ((u64)1<<gpe); + + return 1; +} +__setup("acpi_mask_gpe=", acpi_gpe_set_masked_gpes); + +void acpi_gpe_apply_masked_gpes(void) +{ + acpi_handle handle; + acpi_status status; + u8 gpe; + + for (gpe = 0; + gpe < min_t(u8, ACPI_MASKABLE_GPE_MAX, acpi_current_gpe_count); + gpe++) { + if (acpi_masked_gpes & ((u64)1<<gpe)) { + status = acpi_get_gpe_device(gpe, &handle); + if (ACPI_SUCCESS(status)) { + pr_info("Masking GPE 0x%x.\n", gpe); + (void)acpi_mask_gpe(handle, gpe, TRUE); + } + } + } +} + void acpi_irq_stats_init(void) { acpi_status status; -- 1.7.10 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
