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author | Toshi Kani <toshi.kani@hp.com> | 2012-11-21 01:36:28 (GMT) |
---|---|---|
committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2012-11-21 22:20:22 (GMT) |
commit | fbfddae696572e57a441252abbd65f7220e06030 (patch) | |
tree | cdd75792b688eb816e32b55b499479de45d5d4c5 /drivers/acpi | |
parent | b59bc2fbb4bb67e486c40cdb6a306c06acbaec06 (diff) | |
download | linux-fbfddae696572e57a441252abbd65f7220e06030.tar.xz |
ACPI: Add acpi_handle_<level>() interfaces
This patch introduces acpi_handle_<level>(), where <level> is
a kernel message level such as err/warn/info, to support improved
logging messages for ACPI, esp. hot-plug operations.
acpi_handle_<level>() appends "ACPI" prefix and ACPI object path
to the messages. This improves diagnosis of hotplug operations
since an error message in a log file identifies an object that
caused an issue. This interface acquires the global namespace
mutex to obtain an object path. In interrupt context, it shows
the object path as <n/a>.
acpi_handle_<level>() takes acpi_handle as an argument, which is
passed to ACPI hotplug notify handlers from the ACPICA. Therefore,
it is always available unlike other kernel objects, such as device.
For example:
acpi_handle_err(handle, "Device don't exist, dropping EJECT\n");
logs an error message like this at KERN_ERR.
ACPI: \_SB_.SCK4.CPU4: Device don't exist, dropping EJECT
ACPI hot-plug drivers can use acpi_handle_<level>() when they need
to identify a target ACPI object path in their messages, such as
error cases. The usage model is similar to dev_<level>().
acpi_handle_<level>() can be used when a device is not created or
is invalid during hot-plug operations. ACPI object path is also
consistent on the platform, unlike device name that gets incremented
over hotplug operations.
ACPI drivers should use dev_<level>() when a device object is valid.
Device name provides more user friendly information, and avoids
acquiring the global ACPI namespace mutex. ACPI drivers also
continue to use pr_<level>() when they do not need to specify device
information, such as boot-up messages.
Note: ACPI_[WARNING|INFO|ERROR]() are intended for the ACPICA and
are not associated with the kernel message level.
Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Tested-by: Vijay Mohan Pandarathil <vijaymohan.pandarathil@hp.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi')
-rw-r--r-- | drivers/acpi/utils.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c index 462f7e3..74437130 100644 --- a/drivers/acpi/utils.c +++ b/drivers/acpi/utils.c @@ -28,6 +28,8 @@ #include <linux/slab.h> #include <linux/init.h> #include <linux/types.h> +#include <linux/hardirq.h> +#include <linux/acpi.h> #include <acpi/acpi_bus.h> #include <acpi/acpi_drivers.h> @@ -457,3 +459,39 @@ acpi_evaluate_hotplug_ost(acpi_handle handle, u32 source_event, #endif } EXPORT_SYMBOL(acpi_evaluate_hotplug_ost); + +/** + * acpi_handle_printk: Print message with ACPI prefix and object path + * + * This function is called through acpi_handle_<level> macros and prints + * a message with ACPI prefix and object path. This function acquires + * the global namespace mutex to obtain an object path. In interrupt + * context, it shows the object path as <n/a>. + */ +void +acpi_handle_printk(const char *level, acpi_handle handle, const char *fmt, ...) +{ + struct va_format vaf; + va_list args; + struct acpi_buffer buffer = { + .length = ACPI_ALLOCATE_BUFFER, + .pointer = NULL + }; + const char *path; + + va_start(args, fmt); + vaf.fmt = fmt; + vaf.va = &args; + + if (in_interrupt() || + acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer) != AE_OK) + path = "<n/a>"; + else + path = buffer.pointer; + + printk("%sACPI: %s: %pV", level, path, &vaf); + + va_end(args); + kfree(buffer.pointer); +} +EXPORT_SYMBOL(acpi_handle_printk); |